U.S. patent application number 17/726945 was filed with the patent office on 2022-08-04 for method and apparatus for transmitting uplink demodulation reference signals.
The applicant listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to Jingxing FU, Chen QIAN, Qi XIONG, Bin YU.
Application Number | 20220248341 17/726945 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-04 |
United States Patent
Application |
20220248341 |
Kind Code |
A1 |
FU; Jingxing ; et
al. |
August 4, 2022 |
METHOD AND APPARATUS FOR TRANSMITTING UPLINK DEMODULATION REFERENCE
SIGNALS
Abstract
A method and an apparatus for transmitting uplink demodulation
reference signals (DMRSs) is provided. The method includes a user
equipment (UE) determines an uplink DMRS format for demodulating a
physical uplink shared channel (PUSCH) according to
frequency-domain resources occupied by the PUSCH, in which the
uplink DMRS format includes a comb occupied by a PUSCH DMRS
sequence. The comb is subcarriers having specified intervals
occupied by demodulation reference signals, and the specified
intervals between the occupied subcarriers are same. For the DMRSs
using the comb format, subcarriers with specific intervals are used
for channel estimation, and values of the channel estimation are
used for data demodulation. The UE transmits uplink information and
the demodulation reference signals on physical resources using the
uplink DMRS format. The present disclosure can improve the
multiplexing ratio of uplink physical resources in a multi-UE
scenario.
Inventors: |
FU; Jingxing; (Beijing,
CN) ; YU; Bin; (Beijing, CN) ; QIAN; Chen;
(Beijing, CN) ; XIONG; Qi; (Beijing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Suwon-si |
|
KR |
|
|
Appl. No.: |
17/726945 |
Filed: |
April 22, 2022 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
16460403 |
Jul 2, 2019 |
11323967 |
|
|
17726945 |
|
|
|
|
15474604 |
Mar 30, 2017 |
10362542 |
|
|
16460403 |
|
|
|
|
International
Class: |
H04W 52/24 20060101
H04W052/24; H04L 5/00 20060101 H04L005/00; H04W 52/14 20060101
H04W052/14; H04W 52/32 20060101 H04W052/32; H04W 72/04 20060101
H04W072/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2016 |
CN |
201610200510.2 |
May 13, 2016 |
CN |
201610320080.8 |
Aug 19, 2016 |
CN |
201610694476.9 |
Sep 20, 2016 |
CN |
201610834849.8 |
Claims
1. A method performed by a terminal in a communication system, the
method comprising: receiving, from a base station, a radio resource
control (RRC) message including configuration information for an
uplink demodulation reference signal (DMRS); receiving, from the
base station, downlink control information (DCI) for scheduling a
physical uplink shared channel (PUSCH); identifying the uplink DMRS
based on the configuration information and the DCI; and
transmitting, to the base station, the identified uplink DMRS with
the PUSCH, wherein the configuration information relates to an
actual number of one or more symbols for the uplink DMRS, wherein
the DCI includes information related to a time-domain orthogonal
cover code (OCC) for the uplink DMRS among a set of time-domain
OCCs, and wherein a length of the respective time-domain OCCs
depends on the actual number of the one or more symbols for the
uplink DMRS.
2. The method of claim 1, wherein, in case that the actual number
of the one or more symbols for the uplink DMRS is 1, the length of
the respective time-domain OCCs is 1, and wherein, in case that the
actual number of the one or more symbols for the uplink DMRS is 2,
the length of the respective time-domain OCCs is 2.
3. The method of claim 1, wherein the information included in the
DCI relates to a frequency-domain offset for the uplink DMRS, and
wherein a start subcarrier for the uplink DMRS depends on the
frequency-domain offset.
4. The method of claim 3, wherein a sequence of the DMRS is mapped
to a time-domain resource and a frequency-domain resource based on
the configuration information, the time-domain OCC, and the
frequency-domain offset.
5. The method of claim 1, wherein the configuration information
relates to a type of the uplink DMRS, and wherein the type of the
uplink DMRS relates to whether one or more subcarriers to which the
uplink DMRS is mapped are adjacent to each other without a
frequency-domain interval or are not adjacent to each other with
the frequency-domain interval.
6. A method performed by a base station in a communication system,
the method comprising: transmitting, to a terminal, a radio
resource control (RRC) message including configuration information
for an uplink demodulation reference signal (DMRS); transmitting,
to the terminal, downlink control information (DCI) for scheduling
a physical uplink shared channel (PUSCH); and receiving, from the
terminal, the uplink DMRS with the PUSCH, wherein the uplink DMRS
is based on the configuration information and the DCI, wherein the
configuration information relates to an actual number of one or
more symbols for the uplink DMRS, wherein the DCI includes
information related to a time-domain orthogonal cover code (OCC)
for the uplink DMRS among a set of time-domain OCCs, and wherein a
length of the respective time-domain OCCs depends on the actual
number of the one or more symbols for the uplink DMRS.
7. The method of claim 6, wherein, in case that the actual number
of the one or more symbols for the uplink DMRS is 1, the length of
the respective time-domain OCCs is 1, and wherein, in case that the
actual number of the one or more symbols for the uplink DMRS is 2,
the length of the respective time-domain OCCs is 2.
8. The method of claim 6, wherein the information included in the
DCI relates to a frequency-domain offset for the uplink DMRS, and
wherein a start subcarrier for the uplink DMRS depends on the
frequency-domain offset.
9. The method of claim 8, wherein a sequence of the DMRS is mapped
to a time-domain resource and a frequency-domain resource based on
the configuration information, the time-domain OCC, and the
frequency-domain offset.
10. The method of claim 6, wherein the configuration information
relates to a type of the uplink DMRS, and wherein the type of the
uplink DMRS relates to whether one or more subcarriers to which the
uplink DMRS is mapped are adjacent to each other without a
frequency-domain interval or are not adjacent to each other with
the frequency-domain interval.
11. A terminal in a communication system, the terminal comprising:
a transceiver; and a controller configured to: receive, from a base
station via the transceiver, a radio resource control (RRC) message
including configuration information for an uplink demodulation
reference signal (DMRS), receive, from the base station via the
transceiver, downlink control information (DCI) for scheduling a
physical uplink shared channel (PUSCH), identify the uplink DMRS
based on the configuration information and the DCI, and transmit,
to the base station via the transceiver, the identified uplink DMRS
with the PUSCH, wherein the configuration information relates to an
actual number of one or more symbols for the uplink DMRS, wherein
the DCI includes information related to a time-domain orthogonal
cover code (OCC) for the uplink DMRS among a set of time-domain
OCCs, and wherein a length of the respective time-domain OCCs
depends on the actual number of the one or more symbols for the
uplink DMRS.
12. The terminal of claim 11, wherein, in case that the actual
number of the one or more symbols for the uplink DMRS is 1, the
length of the respective time-domain OCCs is 1, and wherein, in
case that the actual number of the one or more symbols for the
uplink DMRS is 2, the length of the respective time-domain OCCs is
2.
13. The terminal of claim 11, wherein the information included in
the DCI relates to a frequency-domain offset for the uplink DMRS,
and wherein a start subcarrier for the uplink DMRS depends on the
frequency-domain offset.
14. The terminal of claim 13, wherein a sequence of the DMRS is
mapped to a time-domain resource and a frequency-domain resource
based on the configuration information, the time-domain OCC, and
the frequency-domain offset.
15. The terminal of claim 11, wherein the configuration information
relates to a type of the uplink DMRS, and wherein the type of the
uplink DMRS relates to whether one or more subcarriers to which the
uplink DMRS is mapped are adjacent to each other without a
frequency-domain interval or are not adjacent to each other with
the frequency-domain interval.
16. A base station in a communication system, the base station
comprising: a transceiver; and a controller configured to:
transmit, to a terminal via the transceiver, a radio resource
control (RRC) message including configuration information for an
uplink demodulation reference signal (DMRS), transmit, to the
terminal via the transceiver, downlink control information (DCI)
for scheduling a physical uplink shared channel (PUSCH), and
receive, from the terminal via the transceiver, the uplink DMRS
with the PUSCH, wherein the uplink DMRS is based on the
configuration information and the DCI, wherein the configuration
information relates to an actual number of one or more symbols for
the uplink DMRS, wherein the DCI includes information related to a
time-domain orthogonal cover code (OCC) for the uplink DMRS among a
set of time-domain OCCs, and wherein a length of the respective
time-domain OCCs depends on the actual number of the one or more
symbols for the uplink DMRS.
17. The base station of claim 16, wherein, in case that the actual
number of the one or more symbols for the uplink DMRS is 1, the
length of the respective time-domain OCCs is 1, and wherein, in
case that the actual number of the one or more symbols for the
uplink DMRS is 2, the length of the respective time-domain OCCs is
2.
18. The base station of claim 16, wherein the information included
in the DCI relates to a frequency-domain offset for the uplink
DMRS, and wherein a start subcarrier for the uplink DMRS depends on
the frequency-domain offset.
19. The base station of claim 18, wherein a sequence of the DMRS is
mapped to a time-domain resource and a frequency-domain resource
based on the configuration information, the time-domain OCC, and
the frequency-domain offset.
20. The base station of claim 16, wherein the configuration
information relates to a type of the uplink DMRS, and wherein the
type of the uplink DMRS relates to whether one or more subcarriers
to which the uplink DMRS is mapped are adjacent to each other
without a frequency-domain interval or are not adjacent to each
other with the frequency-domain interval.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a continuation application of prior
application Ser. No. 16/460,403, filed on Jul. 2, 2019, which will
be issued as U.S. Pat. No. 11,323,967 on May 3, 2022; which is a
continuation application of prior application Ser. No. 15/474,604,
filed on Mar. 30, 2017, which has been issued as U.S. Pat. No.
10,362,542 on Jul. 23, 2019; which was based on and claimed
priority under 35 U.S.C. .sctn. 119(a) of a Chinese patent
application filed on Mar. 31, 2016, in the State Intellectual
Property Office and assigned Serial number 201610200510.2, and of a
Chinese patent application filed on May 13, 2016, in the State
Intellectual Property Office and assigned Serial number
201610320080.8, and of a Chinese patent application filed on Aug.
19, 2016, in the State Intellectual Property Office and assigned
Serial number 201610694476.9, and of a Chinese patent application
filed on Sep. 20, 2016, in the State Intellectual Property Office
and assigned Serial number 201610834849.8, the disclosure of each
of which is incorporated by reference herein in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates to radio communication
systems. More particularly, the present disclosure relates to a
method and an apparatus for transmitting uplink demodulation
reference signals.
BACKGROUND
[0003] At present, a long term evolution (LTE) system supports two
types of duplex frequency division duplex (FDD) and time division
duplex (TDD). LTE transmission includes transmission from a base
station (an evolved nodeB (eNB)) to a user equipment (UE) (downlink
(DL)), and transmission from the UE to the base station (uplink
(UL)). In a TDD system, downlink and uplink are transmitted in a
same carrier at different times, and in a FDD system, downlink and
uplink are transmitted in different carriers.
[0004] FIG. 1 is a schematic diagram of an LTE TDD frame structure
according to the related art.
[0005] Referring to FIG. 1, each radio frame is 10 ms long, and is
equally divided into two half frames having a length of 5 ms each.
Each half frame includes 8 timeslots having a length of 0.5 ms each
and 3 special fields, i.e., a downlink pilot timeslot (DwPTS), a
guard period (GP), and an uplink pilot timeslot (UpPTS). An overall
length of the 3 special fields is 1 ms. Each subframe consists of
two consecutive timeslots.
[0006] In an LTE system, when uplink data are transmitted on a
physical uplink shared channel (PUSCH), a demodulation reference
signal (DMRS) is required to estimate channels.
[0007] FIG. 2 is a schematic diagram of a PUSCH and DMRS
configuration according to the related art.
[0008] Referring to FIG. 2, for a normal cyclic prefix (CP)
configuration, 12 single carrier-frequency division multiple access
(SC-FDMA) symbols are used as PUSCHs and 2 SC-FDMA symbols are used
as DMRSs. For an extended cyclic prefix (CP) configuration, 10
SC-FDMA symbols are used for PUSCHs, and 2 SC-FDMA symbols are used
for DMRSs. A DMRS sequence is generated from the following formula:
r.sub.PUSCH(mM.sub.sc.sup.RS+n)=w(m)r.sub.u,v.sup.(.alpha.)(n),
where m=0, 1, representing different SC-FDMA symbols at timeslot 0
and timeslot 1, and n=0, 1, . . . , M.sub.sc.sup.RS-1, representing
subcarriers for PUSCHs and DMRSs. r.sub.u,v.sup.(.alpha.)(n)
represents the DMRS sequence, and a specific method of generating
it may be seen in the version V8.9.0 (2009 December) of 3GPP TS
36.211. M.sub.sc.sup.RS represents the number of subcarriers
allocated to the UE for the PUSCHs, and .alpha. represents a cyclic
shift (CS). Orthogonal cover code (OCC) w(m)(m=0, 1) includes [w(0)
w(1)]=[1 1] and [w(0) w(1)]=[1 -1].
[0009] FIG. 3 is a schematic diagram of a DMRS configuration of
different UEs according to the related art.
[0010] Referring to FIG. 3, when PUSCH frequency-domain resources
allocated to different UEs overlap completely, DMRSs adopting
different cyclic shifts of a same Zadoff-Chu sequence are
orthogonal, and DMRSs adopting different OCCs of a same Zadoff-Chu
sequence are orthogonal too. When the PUSCH frequency-domain
resources allocated to the different UEs overlap incompletely,
DMRSs using different cyclic shifts of a Zadoff-Chu sequence are
not orthogonal.
[0011] FIG. 4 is a schematic diagram of a DMRS configuration of
different UEs according to the related art.
[0012] Referring to FIG. 4, DMRSs using different OCCs of a
Zadoff-Chu sequence are orthogonal. However, if there are two
SC-FDMA symbols in the time domain used as DMRSs, there will be
only two orthogonal OCCs, and, when there are more than two UEs of
uplink PUSCH shared resources, and PUSCH frequency-domain resources
allocated for PUSCH of the UEs overlap incompletely, there will not
be enough orthogonal DMRSs in the traditional art to make more UEs
multiplex uplink physical resources. For example, in this case,
when there are multiple UEs, the multiplexing ratio of the uplink
physical resources will be relatively low.
[0013] The above information is presented as background information
only to assist with an understanding of the present disclosure. No
determination has been made, and no assertion is made, as to
whether any of the above might be applicable as prior art with
regard to the present disclosure.
SUMMARY
[0014] Aspects of the present disclosure are to address at least
the above-mentioned problems and/or disadvantages and to provide at
least the advantages described below. Accordingly, an aspect of the
present disclosure is to provide a method and an apparatus for
transmitting uplink demodulation reference signals to increase the
multiplexing ratio of uplink physical resources in a multi-UE
scenario.
[0015] Another aspect of the present disclosure is to provide a
method for transmitting uplink demodulation reference signals
(DMRSs), including determining, by a user equipment (UE), an uplink
DMRS format for demodulating a physical uplink shared channel
(PUSCH) according to frequency-domain resources occupied by the
PUSCH, transmitting, by the UE, uplink information and the
demodulation reference signals on physical resources using the
uplink DMRS format, wherein the uplink DMRS format comprises a comb
occupied by a PUSCH DMRS sequence, and the comb including
subcarriers having specified intervals occupied by demodulation
reference signals, and the specified intervals between the occupied
subcarriers are same, transmitting, by the UE, uplink information
and the demodulation reference signals on physical resources using
the uplink DMRS format.
[0016] In an embodiment of the present disclosure, the uplink DMRS
format further includes at least one of the following formats a
cyclic shift (CS) of the PUSCH DMRS sequence, and an orthogonal
cover code (OCC) of the PUSCH DMRS sequence.
[0017] In an embodiment of the present disclosure, when the PUSCH
is scheduled by control signaling, and determining the uplink DMRS
format for demodulating the PUSCH includes determining, by the UE,
a candidate set from a set of OCCs, a set of CSs, and a set of
combs to be used by the UE by receiving higher layer signaling or
by being preset, and determining an OCC to be used from the set of
OCCs, and/or determining a CS to be used from the set of CSs,
and/or determining a comb to be used from the set of combs by
receiving physical layer signaling, or, determining, first by the
UE, the candidate set from the set of OCCs, the set of CSs, and the
set of combs to be used by the UE by being preset, and determining
the OCC to be used from the set of OCCs, and/or determining the CS
to be used from the set of CSs, and/or determining the comb to be
used from the set of combs by receiving higher layer signaling, or,
determining, by the UE, the OCC, and/or the CS, and/or the comb to
be used by receiving higher layer signaling directly. In an
embodiment of the present disclosure, determining the OCC to be
used from the set of OCCs, and/or determining the CS to be used
from the set of CSs, and/or determining the comb to be used from
the set of combs by receiving physical layer signaling, includes
determining, by the UE, the OCC to be used from the set of OCCs,
and/or determining the CS to be used from the set of CSs, and/or
determining the comb to be used from the set of combs, according to
a corresponding number of bits of signaling in downlink control
information (DCI) received, in which the OCC, the CS or the comb
are instructed by the corresponding numbers of bits of signaling in
DCI.
[0018] In an embodiment of the present disclosure, determining, by
the UE, the OCC, and/or the CS, and/or the comb to be used by
receiving higher layer signaling directly includes determining,
according to higher layer signaling, a set of PRB numbers possibly
allocated to the PUSCH of the UE, and determining an OCC, a CS,
and/or a comb for a PUSCH demodulation reference signal of each PRB
number in the set of PRB numbers.
[0019] In an embodiment of the present disclosure, the PUSCH has
control signaling scheduling, and determining the uplink
demodulation reference signal format for demodulating the PUSCH
includes determining a set of combinations of OCC and comb
according to being configured by higher layer signaling or
according to being preset, determining a combination of OCC and
comb to be used by the DMRSs of the UE from the set of combinations
of OCC and comb according to being configured by higher layer
signaling or according to being instructed by physical layer
signaling, in which a CS to be used by the DMRSs of the UE is
configured separately by higher layer signaling, or instructed by
physical layer signaling separately, or determined by being preset
separately, or, determining a set of combinations of OCC, comb, and
CS according to being configured by higher layer signaling or
according to being preset, and determining a combination of OCC,
comb, and CS to be used by the DMRSs of the UE from the set of
combinations of OCC, comb, and CS according to being configured by
higher layer signaling or according to being instructed by physical
layer signaling.
[0020] In an embodiment of the present disclosure, when the
combination of OCC and comb to be used is instructed by physical
layer signaling, the method includes instructing the combination of
OCC and comb to be used using instruction signaling of the
combination of OCC and comb in DCI, and determining, by the UE, the
combination of OCC and comb to be used by the DMRSs of the UE from
the set of combinations of OCC and comb, according to instruction
signaling of the combination of OCC and comb in DCI received by the
UE, or when the combination of OCC, comb, and CS to be used is
instructed by physical layer signaling, the method includes
instructing the combination of OCC, comb, and CS to be used using
instruction signaling of the combination of OCC, comb, and CS in
DCI, and determining, by the UE, the combination of OCC, comb, and
CS to be used by the DMRSs of the UE from the set of combinations
of OCC, comb, and CS, according to instruction signaling of the
combination of OCC, comb, and CS in DCI received by the UE.
[0021] In an embodiment of the present disclosure, determining the
set of combinations of OCC, comb, and CS according to being
configured by higher layer signaling or according to being preset
by the protocol includes determining the number L of DMRSs
currently required, and if L is smaller than a maximum of the
number of the combinations of OCC, comb, and CS, determining a
subset of the set of combinations of OCC, comb, and CS according to
being configured by higher layer signaling or according to being
preset, in which the number of combinations of OCC, comb, and CS in
the subset is L, determining a combination of OCC, comb, and CS to
be used by the DMRSs of the UE from the subset.
[0022] In an embodiment of the present disclosure, when the
combination of OCC, comb, and CS to be used is instructed by
physical layer signaling, the number of bits required for
instruction signaling of the combination of OCC, comb, and CS in
DCI is a ceiling value of log 2(L).
[0023] In an embodiment of the present disclosure, in case of a
PUSCH without control signaling, determining the uplink
demodulation reference signal format for demodulating the PUSCH
includes determining, first by the UE, a set of OCCs, a set of CSs,
and a set of combs to be used by the DMRS of the UE as a candidate
set by receiving higher layer signaling or according to presetting,
and determining an OCC to be used from the set of OCCs, and/or
determining a CS to be used from the set of CSs, and/or determining
a comb to be used from the set of combs by being configured by
higher layer signaling or by initiative selection by the UE, or,
determining directly, by the UE, the OCC, and/or the CS, and/or the
comb to be used by the DMRSs of the UE by receiving higher layer
signaling.
[0024] In an embodiment of the present disclosure, determining
directly, by the UE, the OCC, and/or the CS, and/or the comb to be
used by the DMRSs of the UE by receiving higher layer signaling
includes determining a set of PRB numbers that are possibly
allocated to the PUSCH of the UE according to higher layer
signaling, and determining an OCC, a CS, and/or a comb for a PUSCH
demodulation reference signal of each PRB number from the set of
PRB numbers.
[0025] In an embodiment of the present disclosure, in case of the
PUSCH without control signaling scheduling, determining the uplink
demodulation reference signal format for demodulating the PUSCH
includes determining a set of combinations of OCC and comb by being
configured by higher layer signaling or according to being preset,
determining a combination of OCC and comb to be used by the DMRSs
of the UE from the set of combinations of OCC and comb by being
configured by higher layer signaling or by being selected
initiatively by the UE, and the CS to be used by the DMRSs of the
UE is configured separately by the UE, or selected initiatively by
the UE, or, determining a set of combinations of OCC, comb, and CS
by being configured by higher layer signaling or by being preset,
determining a combination of OCC, comb, and CS to be used by the
DMRSs of the UE from the set of combinations of OCC, comb, and CS
by being configured by higher layer signaling or by being selected
initiatively by the UE.
[0026] In an embodiment of the present disclosure, determining the
set of combinations of OCC, comb, and CS by being configured by
higher layer signaling or by being preset includes determining the
number L of DMRSs currently required, and if L is smaller than the
maximum number of combinations of OCC, comb, and CS, determining a
subset of the set of combinations of OCC, comb, and CS according to
being configured by higher layer signaling or according to being
preset, in which the number of combinations of OCC, comb, and CS in
the subset is L, and determining a combination of OCC, comb, and CS
to be used by the DMRSs of the UE from the subset.
[0027] In an embodiment of the present disclosure, the method
further includes determining, by the UE, power of transmitting the
DMRSs according to whether the DMRSs use a comb and according to a
format of the comb used.
[0028] In an embodiment of the present disclosure, the method
further includes if the UE uses a comb format to transmit the
DMRSs, total power of all sub-carriers for transmitting DMRSs in
each single carrier-frequency division multiplexing (SC-FDM) symbol
is equal to total power of all sub-carriers for transmitting PUSCHs
in each SC-FDM symbol.
[0029] In an embodiment of the present disclosure, the method
further includes if the UE uses the comb format to transmit the
DMRSs, transmission power of each DMRS subcarrier of the UE is
equal to transmission power of each PUSCH subcarrier of the UE.
[0030] In an embodiment of the present disclosure, the method
further includes if the UE uses the comb format to transmit the
DMRSs, transmission power of a DMRS on each DMRS sub-carrier of the
UE is not equal to transmission power of a PUSCH on each PUSCH
sub-carrier of UE, and total transmission power of all sub-carriers
of DMRSs in each SC-FDM symbol being equal to total transmission
power of all sub-carriers of PUSCHs in each PUSCH SC-FDM symbol,
or, transmission power of a DMRS in each subcarrier of each SC-FDM
symbol of the UE being PDMRS=min{RPF*PPUSCH, P1}, where PDMRS is
the transmission power in each subcarrier of each DMRS SC-FDM
signal of the UE, PPUSCH is the transmission power in each
subcarrier of each PUSCH SC-FDM signal of UE, P1 is the allowed
maximum of transmission power in each subcarrier of each DMRS
SC-FDM signal of the UE and transmission power in each subcarrier
of each PUSCH SC-FDM signal of the UE.
[0031] In an embodiment of the present disclosure, the method
further includes determining, by the UE, the DMRS sequence to be
transmitted according to whether the DMRSs use the comb and
according to the format of the comb.
[0032] In an embodiment of the present disclosure, if the number of
PRBs of the PUSCH scheduled by the UE in the frequency-domain
resources is an integral multiple M of a DMRS repetition factor
(RPF), a length of the DMRS sequence is M times of the number of
PRBs, or, the DMRS sequence transmitted by the UE satisfies the
following conditions when frequency-domain resource of PUSCHs
scheduled by UEs are same, and RPFs of DMRSs are same, if CSs of
two DMRS sequences are different, the two DMRS sequences are
orthogonal, or using the number of subcarriers of the PUSCH
scheduled by the UE in the frequency-domain resources as a length
of the DMRS sequence, and punching or truncating the DMRS sequence
according to the length of the DMRS sequence, where a punching
process is that within a range of scheduled PRBs, the DMRS sequence
in positions of transmitting DMRSs is transmitted, and the DMRS
sequence in other positions will not be transmitted, and a
truncation process is that within the range of the scheduled PRBs,
the UE transmits the DMRS sequence successively on DMRS positions
according to an order and a length of the DMRS sequence, and the
rest of the DMRS sequence is not transmitted.
[0033] In an embodiment of the present disclosure, determining the
uplink DMRS format for demodulating the PUSCH includes if the UE
knowing that the DMRS format comprises the comb by receiving higher
layer signaling, the UE determining whether to use a DMRS with a
comb according to the PUSCH scheduled by the UE, or determining
whether to use the DMRS with the comb, and determining a RPF of a
comb contained in the DMRS with the comb in response to determining
to use the DMRS with the comb.
[0034] In an embodiment of the present disclosure, the UE
determining whether to use the DMRS with the comb according to the
PUSCH scheduled by the UE, or determining whether to use the DMRS
with the comb, and determining the RPF of the comb contained in the
DMRS with the comb in response to determining to use the DMRS with
the comb includes if the number of PRBs contained in the PUSCH
scheduled by the UE being not a multiple of N, the UE using a DMRS
without a comb, and if the number of PRBs contained in the PUSCH
scheduled by the UE being a multiple of N, the UE using the DMRS
with the comb, where N is a positive integer, or, if the number of
PRBs contained in the PUSCH scheduled by the UE being not a
multiple of N and number of REs in frequency domain is smaller than
M, the UE using a DMRS without a comb, and if the number of PRBs
contained in the PUSCH scheduled by the UE being a multiple of N,
or the number of PRBs contained in the PUSCH scheduled by the UE
being not a multiple of N and number of REs in frequency domain is
equal or larger than M, the UE using the DMRS with the comb, where
N is a positive integer, or, if the number of PRBs contained in the
PUSCH scheduled by the UE being not a multiple of N1, the UE using
the DMRS without the comb, and if the number of PRBs contained in
the PUSCH scheduled by the UE being a multiple of N1 but not a
multiple of N2, the UE using the DMRS with the comb, the comb of
which has a PRF being M1, and if the number of PRBs contained in
the PUSCH scheduled by the UE being a multiple of N1 and also being
a multiple of N2, the UE using the DMS with the comb, the comb of
which has a RPF being M2, where N1, N2, M1 and M2 are positive
integers, N2 is a multiple of N1, and M2 is a multiple of M1, or,
if the UE knowing that a DMRS contains a comb and that a RPF of the
comb is M1 by receiving higher layer signaling, if the number of
PRBs contained in the PUSCH scheduled by the UE being not a
multiple of N1, the UE using the DMRS without the comb, and if the
PUSCH scheduled by the UE being a multiple of N1, the UE using the
DMRS containing the comb, the RPF of which is M1, where N1 and M1
are positive integers, or, if the UE knowing that a DMRS contains a
comb and that a RPF of the comb is M2 by receiving higher layer
signaling, if the number of PRBs contained in the PUSCH scheduled
by the UE being not a multiple of N2, the UE using the DMRS without
the comb, and if the number of PRBs contained in the PUSCH
scheduled by the UE being a multiple of N2, the UE using the DMRS
that contains the comb, the RPF of which is M2, where N2 and M2 are
positive integers, N2 is a multiple of N1, and M2 is a multiple of
M1, or, if the UE knowing that a DMRS contains a comb by receiving
higher layer signaling, the UE deciding whether to use the DMRS
containing the comb and determining a RPF of the comb contained in
the DMRS according to information bit instruction in UL DCI of the
PUSCH scheduled by the UE, or, if the UE knowing that a DMRS
contains a comb by receiving higher layer signaling, the UE
deciding whether to use the DMRS containing the comb according to
information bit instruction in UL DCI of the PUSCH scheduled by the
UE, or, if the UE knowing that a DMRS contains a comb by receiving
higher layer signaling, and knowing a RPF value by receiving higher
layer signaling, the UE deciding whether to use the DMRS containing
the comb and a comb value of the comb contained in the DMRS
according to information bit instruction in UL DCI of the PUSCH
scheduled by the UE, or, if the UE knowing that a DMRS contains a
comb by receiving higher layer signaling, the UE determining
whether to use the DMRS containing the comb, determining a RPF
value of the comb contained in the DMRS, and determining combs with
different RPF values according to information bit instruction in UL
DCI of the PUSCH scheduled by the UE.
[0035] In accordance with another aspect of the present disclosure,
an apparatus for transmitting the uplink demodulation reference
signal is provided. The apparatus includes an uplink transmission
format determination device configured to determine an uplink
demodulation reference signal format for demodulating a PUSCH
according to frequency-domain resources occupied by the PUSCH, in
which, the demodulation reference signal format includes a comb
occupied by a PUSCH demodulation reference signal sequence, the
comb including subcarriers having specified intervals occupied by
demodulation reference signals, wherein the specified intervals
between the occupied subcarriers are same, and a transmission
device configured to transmit uplink information and the
demodulation reference signals on physical resources using the
uplink DMRS format.
[0036] When the uplink demodulation reference signal format for
demodulating the PUSCH is determined, a comb may be selected. The
comb includes subcarriers having specified intervals occupied by
demodulation reference signals, and the specified intervals between
the occupied subcarriers are same. For example, a comb structure
can be used to transmit demodulation reference signals.
Demodulation reference signals with different combs are orthogonal,
and when frequency-domain resources allocated to PUSCHs of
different UEs overlap completely, demodulation reference signals
using different combs of the UEs are orthogonal, and when
frequency-domain resources allocated to PUSCHs of different UEs
overlap incompletely, demodulation reference signals using
different combs of the UEs are orthogonal. When the comb structure
is used to transmit DMRSs, on one hand, the capacity of the DMRSs
is increased, so that more UEs can multiplex the uplink physical
resources, on the other hand, when the PUSCH frequency-domain
resources allocated to different UEs overlap incompletely, and the
UEs are going to multiplex the uplink physical resources, the DMRSs
using different CSs are not orthogonal, but, the DMRSs using
different combs are orthogonal, and more UEs can still multiplex
the uplink physical resources. Hence, the present disclosure can
increase the number of DMRSs that keep orthogonal when the PUSCH
frequency-domain resources overlap incompletely, and thus can
improve the multiplexing ratio of the uplink physical resources in
a multi-user scenario.
[0037] Other aspects, advantages, and salient features of the
disclosure will become apparent to those skilled in the art from
the following detailed description, which, taken in conjunction
with the annexed drawings, discloses various embodiments of the
present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] The above and other aspects, features, and advantages of
certain embodiments of the present disclosure will be more apparent
from the following description taken in conjunction with the
accompanying drawings, in which:
[0039] FIG. 1 is a schematic diagram of a long term evolution time
division duplex (LTE TDD) frame structure according to the related
art;
[0040] FIG. 2 is a schematic diagram of a physical uplink shared
channel (PUSCH) and demodulation reference signals (DMRS)
configuration according to the related art;
[0041] FIG. 3 is a schematic diagram of a DMRS configuration of
different user equipment (UEs) according to the related art;
[0042] FIG. 4 is a schematic diagram of a DMRS configuration of
different UEs according to the related art;
[0043] FIG. 5 is a schematic diagram of a flowchart of a method for
transmitting uplink demodulation reference signals in according to
an embodiment of the present disclosure;
[0044] FIG. 6 is a schematic diagram of sub-carriers occupied by
UEs according to an embodiment of the present disclosure;
[0045] FIG. 7 is a schematic diagram of transmission resources of a
UE according to an embodiment of the present disclosure;
[0046] FIG. 8 is a schematic diagram of PUSCH resources of physical
resource blocks (PRBs) of a UE according to an embodiment of the
present disclosure;
[0047] FIG. 9 is a schematic diagram of the numbers of PRBs and
Orthogonal cover code (OCCs) of different UEs according to an
embodiment of the present disclosure; and
[0048] FIG. 10 is a schematic diagram of start subcarriers
allocated to a UE according to an embodiment of the present
disclosure.
[0049] Throughout the drawings, like reference numerals will be
understood to refer to like parts, components, and structures.
DETAILED DESCRIPTION
[0050] The following description with reference to the accompanying
drawings is provided to assist in a comprehensive understanding of
various embodiments of the present disclosure as defined by the
claims and their equivalents. It includes various specific details
to assist in that understanding but these are to be regarded as
merely exemplary. Accordingly, those of ordinary skill in the art
will recognize that various changes and modifications of the
various embodiments described herein can be made without departing
from the scope and spirit of the present disclosure. In addition,
descriptions of well-known functions and constructions may be
omitted for clarity and conciseness.
[0051] The terms and words used in the following description and
claims are not limited to the bibliographical meanings, but, are
merely used by the inventor to enable a clear and consistent
understanding of the present disclosure. Accordingly, it should be
apparent to those skilled in the art that the following description
of various embodiments of the present disclosure is provided for
illustration purpose only and not for the purpose of limiting the
present disclosure as defined by the appended claims and their
equivalents.
[0052] It is to be understood that the singular forms "a," "an,"
and "the" include plural referents unless the context clearly
dictates otherwise. Thus, for example, reference to "a component
surface" includes reference to one or more of such surfaces.
[0053] By the term "substantially" it is meant that the recited
characteristic, parameter, or value need not be achieved exactly,
but that deviations or variations, including for example,
tolerances, measurement error, measurement accuracy limitations and
other factors known to those of skill in the art, may occur in
amounts that do not preclude the effect the characteristic was
intended to provide.
[0054] Higher layer signaling in the present disclosure includes
system information or user equipment (UE)-specific higher layer
signaling, and it has this meaning in the following of the present
disclosure, if not otherwise specified.
[0055] To achieve the objects of the present disclosure, the
present disclosure provides a method for transmitting uplink
demodulation reference signals.
[0056] FIG. 5 is a schematic diagram of a flowchart of a method for
transmitting uplink demodulation reference signals according to an
embodiment of the present disclosure.
[0057] Referring to FIG. 5, the method includes the following
operations:
[0058] Operation 501: a UE determines an uplink demodulation
reference signal format for demodulating a physical uplink shared
channel (PUSCH) according to frequency-domain resources occupied by
the PUSCH.
[0059] The frequency-domain resources include the number and
positions of physical resource blocks (PRBs) occupied by the
PUSCH.
[0060] The demodulation reference signal format for the PUSCH
herein includes: a cyclic shift (CS) of a PUSCH demodulation
reference signal sequence, and/or an orthogonal cover code (OCC) of
the PUSCH demodulation reference signal sequence, and/or a comb
occupied by the PUSCH demodulation reference signal sequence. For
example, the demodulation reference signal format includes at least
one of the CS, OCC, or comb.
[0061] The comb means that PUSCH demodulation reference signals do
not occupy all same subcarriers allocated to the UE for PUSCH
transmission, but occupy part of the subcarriers allocated to the
UE for PUSCH transmission. The demodulation reference signals
occupy subcarriers that have specified intervals, and the intervals
between the subcarriers are the same. The intervals between the
subcarriers are called repetition factor (RPF).
[0062] FIG. 6 is a schematic diagram of sub-carriers occupied by
UEs according to an embodiment of the present disclosure. FIG. 7 is
a schematic diagram of transmission resources of a UE according to
an embodiment of the present disclosure.
[0063] Referring to FIG. 6, a schematic diagram of sub-carriers
occupied by UEs, where RPF=4, is illustrated. For example,
subcarriers, an interval between which is 4 and a comb of which is
0, are allocated to a UE as a demodulation reference signal, and a
start subcarrier of the demodulation reference signals (DMRS) and a
start subcarrier of a PUSCH are the same, subcarriers, an interval
between which is 4 and a comb of which is 1, are allocated to
another UE as a demodulation reference signal, and a start
subcarrier of the DMRS equals to the start subcarrier of the PUSCH
plus 1, subcarriers, an interval between which is 4 and a comb of
which is 2, are allocated to another UE as a demodulation reference
signal, and a start subcarrier of the DMRS equals to the start
subcarrier of the PUSCH plus 2, and subcarriers, an interval
between which is 4 and a comb of which is 3, are allocated to
another UE as a demodulation reference signal, and a start
subcarrier of the DMRS equals to the start subcarrier of the PUSCH
plus 3. The demodulation reference signals having different combs
are orthogonal, and when the PUSCH frequency-domain resources
allocated to different UEs overlap completely, the demodulation
reference signals using different combs of the UEs are orthogonal,
and when the PUSCH frequency-domain resources allocated to
different UEs overlap incompletely, the demodulation reference
signals using different combs are still orthogonal. When DMRSs are
transmitted using the comb structure, on the one hand, the capacity
of the DMRSs is increased, so that more UEs can multiplex the
uplink physical resources, on the other hand, when the PUSCH
frequency-domain resources allocated to different UEs overlap
incompletely, and UEs are going to multiplex the uplink physical
resources, the DMRSs using different CSs are not orthogonal, but,
the DMRSs using different combs are orthogonal, and more UEs can
still multiplex the uplink physical resources.
[0064] Referring to FIG. 7, for DMRSs of a UE using the comb
structure, channel estimation is performed for them using
subcarriers having a specified interval, and then data demodulation
is performed using a value of channel estimation. However, PUSCH
data of the UE are transmitted on all the subcarriers, and on
subcarriers between the DMRSs, channels of these subcarriers should
be estimated out too, but there are no DMRS on these subcarriers,
and therefore, DMRSs on these subcarriers should be obtained by
performing interpolation using DMRSs on other subcarriers, as shown
in FIG. 7.
[0065] Operation 502: the UE transmits uplink information and the
demodulation reference signals on physical resources using the
uplink DMRS format.
[0066] Corresponding to the above method in the present disclosure,
the present disclosure also discloses an apparatus for transmitting
uplink demodulation reference signals, including an uplink
transmission format determination device configured to determine an
uplink demodulation reference signal format for demodulating a
PUSCH according to frequency-domain resources occupied by the
PUSCH, in which, the demodulation reference signal format includes
at least one of the following formats: a cyclic shift (CS) of a
PUSCH demodulation reference signal sequence, an orthogonal cover
code (OCC) of the PUSCH demodulation reference signal sequence, or
a comb occupied by the PUSCH demodulation reference signal
sequence, the comb is a demodulation reference signal occupies
subcarriers having specified intervals, and the intervals between
the occupied subcarriers are the same, and for demodulation
reference signals using the comb format, channel estimation is
performed for them using subcarriers having a specified interval,
and then data demodulation is performed using a value of channel
estimation, and a transmission device configured to transmit uplink
information and the demodulation reference signals on physical
resources using the uplink DMRS format. The technical solution of
the present disclosure will be further described with reference to
several embodiments in the following. For PUSCHs with or without
control signaling scheduling, the method for transmitting
demodulation reference signals in the present disclosure are
different, which will be described respectively in the
following.
Embodiment 1
[0067] In this embodiment 1, the method for transmitting
demodulation reference signals when a PUSCH has control signaling
scheduling will be described, and in this case the PUSCH is
scheduled by control signaling uplink downlink control information
(UL DCI).
[0068] FIG. 8 is a schematic diagram of PUSCH resources of physical
resource blocks (PRBs) of a UE according to an embodiment of the
present disclosure.
[0069] Referring to FIG. 8, there are two situations of allocating
resources for UEs. A situation is that the numbers of PRBs of
frequency-domain resources allocated for the UEs to transmit PUSCHs
are related to positions of the frequency-domain resources, e.g.,
the numbers of PRBs used by the UEs at different positions of the
frequency-domain resources being different, and in this way, either
the frequency-domain resources used by the UEs to transmit the
PUSCHs overlap completely, or the frequency-domain resources used
by the UEs to transmit the PUSCHs do not overlap at all, and
frequency-domain resources for transmitting PUSCHs, PRBs of which
are 1, 2, and 4, do not overlap at all, but they are at different
frequency-domain positions, referring to FIG. 8. In this situation,
as long as one of the three factors, DMRS OCC, DMRS comb and DMRS
CS, is different, DMRSs are orthogonal. Another situation is that
the numbers of PRBs of frequency-domain resources allocated for the
UEs to transmit PUSCHs are independent of positions of the
frequency-domain resources, e.g., the numbers of PRBs that the UEs
use at the same position of the frequency-domain resources may be
same or different, and in this way, the frequency-domain resources
used by the UEs to transmit PUSCHs may overlap completely, and the
frequency-domain resources used by the UEs to transmit PUSCHs may
overlap incompletely. In this situation, as long as one of the two
factors, the DMRS OCC and DMRS comb, is different, DMRSs are
orthogonal, and when CSs of DMRSs are different, the DMRSs may be
orthogonal or not.
[0070] First, assume that the number of OCCs of a DMRS is M (M is a
positive integer larger than or equal to 1, and it is configured by
higher layer signaling (including system information or UE-specific
higher layer signaling), or instructed by physical layer signaling,
or determined according to presetting, e.g., M=1, 2, 4, 8, and the
like), and a set of OCCs is {OCC0, . . . OCCm, . . . , OCCM-1},
which is determined according to presetting. The number of combs of
the DMRS is N (N is a positive integer larger than or equal to 1,
and it is configured by higher layer signaling (including system
information or UE-specific higher layer signaling), or instructed
by physical layer signaling, or determined according to presetting,
e.g., N=1, 2, 4, 8, and the like), and the set of combs is {comb0,
. . . , combn, . . . , combN-1}, and it is determined according to
presetting. The number of the CSs of the DMRS is q (q is a positive
integer larger than or equal to 1, and it is configured by higher
layer signaling (including system information or UE-specific higher
layer signaling), or instructed by physical layer signaling, or
determined according to presetting, e.g., q=1, 2, 4, 8, 12, and the
like), and the set of CSs is as shown in Table 9 or Table 10, or it
is determined according to presetting.
[0071] In the present disclosure, the presetting may include a
communication protocol that the evolved nodeB (eNB) and the UE both
agree on, e.g., a third generation partnership project (3GPP)
protocol.
[0072] In addition, it is described in the foregoing that three
factors can increase the number of orthogonal DMRSs, but according
to different channel situations and different requirements for the
number of orthogonal DMRSs, there will not always be the three
factors for a specific DMRS. A DMRS may include one of the three
factors, i.e., the DMRS may include the OCC factor only, or the
DMRS may include the CS factor only, or the DMRS may include the
comb factor only, or a DMRS may include any two of the three
factors, i.e., the DMRS includes the OCC and CS factors, or the
DMRS includes the OCC and comb factors, or the DMRS includes the
comb, and CS factors, or a DMRS may include all of the three
factors, i.e., the DMRS includes the OCC, CS and comb factors. A UE
knows how many factors and which factors are included in a DMRS of
the UE by receiving higher layer signaling configuration, i.e., the
UE in connecting state obtains the type of the DMRS by receiving
higher layer signaling, and the type of the DMRS specifies how many
factors and which factors are included in the DMRS. For example, as
specified by an existing 3GPP protocol, if higher layer signaling
configures that Activate-DMRS-with OCC is true, then a DMRS
includes the OCC and CS factors, and if no higher layer signaling
configures Activate-DMRS-with OCC, then a DMRS includes the CS
factor only. Or how many factors and which factors being included
in default state of a DMRS of a UE is determined according to a
protocol, e.g., a DMRS of a PUSCH scheduled by DCI scrambled using
a cell-radio network temporary identity (C-RNTI) only includes the
CS factor. For example, when the comb factor is introduced, new
higher layer signaling, Activate DMRS-with OCC and comb may be
introduced, and if higher layer signaling configures that
Activate-DMRS-with OCC and comb is true, then a DMRS includes the
OCC, CS and comb factors, i.e., the DMRSs of the UEs using
different CSs, the DMRSs of the UEs using different OCCs, and the
DMRSs of the UEs using different combs, if higher layer signaling
configures that Activate-DMRS-with OCC is true, and no higher layer
signaling configures that Activate-DMRS-with OCC and comb is true,
then a DMRS includes the CS and OCC factors, i.e., the DMRSs of the
UEs using different CSs, the DMRSs of the UEs using different OCCs,
and the DMRSs of the UEs using the same subcarriers with those used
by the PUSCH, if no higher layer signaling configures that
Activate-DMRS-with OCC and Activate-DMRS-with OCC and comb are
true, then a DMRS includes the CS factor only. New higher layer
signaling may be introduced to determine different numbers of
factors and different factors included in a DMRSs. Or, new higher
layer signaling, Activate-DMRS-with comb, is introduced, and if
higher layer signaling configures that Activate-DMRS-with comb is
true, then a DMRS includes the comb and CS factors.
[0073] In the following, several methods for transmitting DMRSs
will be described, assuming that higher layer signaling configures
that Activate-DMRS-with OCC and comb is true, and that a DMRS
includes the OCC, CS and comb factors.
Method 1:
[0074] A UE may determine an OCC, and/or a CS, and/or a comb of a
DMRS to be used by the UE by receiving higher layer signaling
(including system information or UE-specific higher layer
signaling) configuration or physical layer signaling instruction,
or according to a protocol.
[0075] Specifically, the following three methods may be
included.
[0076] The first method is that the UE determines a candidate set
from a set of OCCs, a set of CSs and a set of combs to be used by
the UE by receiving higher layer signaling (including system
information or UE-specific higher layer signaling) or according to
a protocol. Then the UE determines an OCC to be used from the set
of OCCs, and/or determines a CS to be used from the set of CSs,
and/or determines a comb to be used from the set of combs by
receiving physical layer signaling.
[0077] The second method is that first the UE determines a
candidate set from a set of OCCs, a set of CSs, and a possible set
of combs to be used by the UE according to a protocol, and then
determines an OCC to be used from the OCC set, and/or a CS to be
used from the CS set, and/or a comb to be used from the set of
combs by receiving higher layer signaling.
[0078] The third method is that the UE determines an OCC, and/or a
CS, and/or a comb to be used by the UE by receiving higher layer
signaling (including system information or UE-specific higher layer
signaling) directly.
[0079] In the following, how to determine a specific OCC, and/or a
CS, and/or a comb from a set of OCCs, a set of CSs and a set of
combs will be described.
[0080] At first, a method for determining OCCs will be described,
in which a set of OCCs is {OCC0, . . . , OCCm, . . . , OCCM-1}. For
example, when the UE determines that the number of SC-FDMA or OFDM
symbols to be used as a DMRS is 2 by receiving higher layer
signaling or according to a protocol, that the number of OCCs is 2,
and that the set of OCCs to be used by the UE is {[w(0) w(1)]=[1
1], [w(0) w(1)]=[1 -1]}, then higher layer signaling (including
system information or UE-specific higher layer signaling) or
physical layer signaling instructs the OCCs to be used by the UE.
When the OCCs to be used by the UE are instructed by physical layer
signaling, 1-bit signaling in downlink control information (DCI)
will instruct the OCCs, and this 1-bit signaling is called OCC
instruction signaling, as shown in Table 1. The UE determines the
OCCs by receiving OCC instruction signaling.
TABLE-US-00001 TABLE 1 Table 1: OCC instruction signaling and OCC
mapping relationship OCC instruction signaling value 0 1 OCC [1 1]
[1 -1]
[0081] Or, for example, when the UE determines that the number of
SC-FDMA or OFDM symbols to be used as the DMRS is 4 by receiving
higher layer signaling or according to a protocol, that the number
of OCCs is 4, and that the set of OCCs [w(0) w(1) w(2) w(3)] to be
used by the UE is {[1 1 1 1], [1 1 -1 -1], [1 -1 -1 1], [1 -1 1
-1]}, then 2-bit signaling in downlink control information (DCI)
will be used to instruct the OCCs, and this 2-bit signaling is
called OCC instruction signaling, as shown in Table 2. The UE
determines the OCCs by receiving OCC instruction signaling.
TABLE-US-00002 TABLE 2 Table 2: OCC instruction signaling and OCC
mapping relationship OCC instruction signaling value 00 01 10 OCC
[1 1 1 1] [1 1 -1 -1] [1 -1 -1 1]
[0082] Or, for example, when the UE determines that the number of
SC-FDMA or OFDM symbols to be used as the DMRS is 4 by receiving
higher layer signaling or according to a protocol, then the
possible number of OCCs is 4. But when the UE determines that the
number of OCCs to be used by the UE is 2 by receiving higher layer
signaling, and that the set of OCCs [w(0) w(1) w(2) w(3)] to be
used by the UE is {[1 1 1 1], [1 1 -1 -1]} 1-bit signaling in
downlink control information (DCI) will instruct the OCCs, and this
1-bit signaling is called OCC instruction signaling, as shown in
Table 3. The UE obtains the OCCs by receiving OCC instruction
signaling.
TABLE-US-00003 TABLE 3 Table 3: OCC instruction signaling and OCC
mapping relationship OCC instruction signaling value 0 1 OCC [1 1 1
1] [1 1 -1 -1]
[0083] When the number of OCCs in the set of OCCs to be used as the
DMRS is other numbers, a similar method may be used to determine
the set of OCCs first, and then determine the OCCs to be used by
the UE by being instructed by higher layer signaling (including
system information or UE-specific higher layer signaling) or
physical layer signaling. When the OCCs to be used by the UE are
instructed by physical layer signaling, and by being instructed by
OCC instruction signaling in DCI, the UE obtains the OCCs by
receiving OCC instruction signaling.
[0084] FIG. 9 is a schematic diagram of the numbers of PRBs and
orthogonal cover codes (OCCs) of different UEs according to an
embodiment of the present disclosure.
[0085] Referring to FIG. 9, an OCC is determined related to the
number of PRBs allocated to a UE for a PUSCH. For example, a set of
PRB numbers possibly to be allocated to the UE for the PUSCH is
determined according to higher layer signaling (including system
information or UE-specific higher layer signaling) or according to
a protocol (for example, PRB numbers allocated possibly to the UE
for the PUSCH are 1, 2, 4, and 8), then an OCC is determined for a
PUSCH demodulation reference signal of each PRB number, for
example, determining an OCC for a PUSCH demodulation reference
signal of each PRB number by a protocol or by higher layer
signaling (including system information or UE-specific higher layer
signaling, which are referred to as higher layer signaling system
information or UE-specific higher layer signaling in the
following). For example, when the PRB numbers allocated possibly to
the UE for the PUSCH are 1, 2, 4, and 8, and available OCCs are {[1
1 1 1], [1 1 -1 -1], [1 -1 -1 1], [1 -1 1 -1]}, a PRB number and
OCC mapping relationship is as shown in Table 4. In this way, when
PRB numbers of PUSCH frequency-domain resources allocated to
different UEs are different, and start PRBs of PUSCH resources
allocated to the UEs are same, by allocating different OCCs to UEs
with different PRB numbers, it is ensured that when the PRB numbers
of PUSCH frequency-domain resources allocated to the UEs are
different, DMRSs of the UEs are orthogonal, as shown in FIG. 9.
TABLE-US-00004 TABLE 4 Table 4: PRB number and OCC mapping
relationship PRB number 1 2 4 8 OCC [1 1 1 1] [1 1 -1 -1] [1 -1 -1
1] [1 -1 1 -1}
[0086] FIG. 10 is a schematic diagram of start subcarriers
allocated to a UE according to an embodiment of the present
disclosure.
[0087] Referring to FIG. 10, a method for determining combs will be
described, in which a set of combs is {comb0, . . . , combn, . . .
, combN-1}. For example, when a UE determines that the number of
combs used for DMRSs is 2 and that the set of combs to be used by
the UE is {0, 1}, by receiving higher layer signaling or by a
protocol, then higher layer signaling (including system information
or UE-specific higher layer signaling) or physical layer signaling
instructs a comb to be used by the UE. For example, when a
repetition factor (RPF) of the DMRSs is 2, there are two combs,
i.e., comb being equal to 0 and comb being equal to 1, higher layer
signaling (including system information or UE-specific higher layer
signaling) or physical layer signaling instructs a comb to be used
by the UE. When a comb to be used by the UE equals to 0,
subcarriers occupied by the UE are subcarriers, an interval between
which is 2, on PRBs allocated for PUSCH of the UE, and a start
subcarrier of a DMRS is a start subcarrier of the PRBs allocated
for PUSCH of the UE, when a comb equals to 1, subcarriers occupied
by the UE are subcarriers, an interval between which is 2, on PRBs
allocated for PUSCH allocated of the UE, and a start subcarrier of
a DMRS is the start subcarrier of the PRBs allocated for PUSCH of
the UE plus 1, as shown in FIG. 10. When the comb used by the UE is
instructed by physical layer signaling, 1-bit signaling in downlink
control information (DCI) will instruct the comb, this 1-bit
signaling is called comb instruction signaling, a comb instruction
signaling and comb mapping relationship is as shown in Table 5. The
UE determines the comb to be used by the UE by receiving comb
instruction signaling.
TABLE-US-00005 TABLE 5 Table 5: comb instruction signaling and comb
mapping relationship comb instruction signaling value 0 1 comb 0
1
[0088] Or, for example, when the UE determines that the number of
combs to be used for DMRSs is 4 and the set of combs to be used by
the UE is {0, 1, 2, 3} by receiving higher layer signaling or by a
protocol, then higher layer signaling (including system information
or UE-specific higher layer signaling) or physical layer signaling
instructs a comb to be used by the UE. When the comb equals to 0,
the subcarriers occupied by the UE are subcarriers, an interval
between which is 4, of the PRBs allocated for PUSCH by the UE, and
a start subcarrier of the DMRS is a start subcarrier of the PRBs
allocated for PUSCH of the UE. When the comb equals to 1,
subcarriers occupied by the UE are subcarriers, an interval between
which is 4, of the PRBs allocated for PUSCH of the UE, and a start
subcarrier of the DMRS is the start subcarrier of the PRBs
allocated for PUSCH of the UE plus 1, when the comb equals to 2,
the subcarriers occupied by the UE are subcarriers, an interval
between which is 4, of the PRBs allocated for PUSCH of the UE, and
a start subcarrier of the DMRS is the start subcarrier of the PRBs
allocated for PUSCH of the UE plus 2, and when the comb equals to
3, the subcarriers occupied by the UE are subcarriers, an interval
between which is 4, of the PRBs allocated for PUSCH of the UE, and
a start subcarrier of the DMRS is the start subcarrier of the PRBs
allocated of the UE plus 3.
[0089] When the comb to be used by the UE is instructed by physical
layer signaling, the comb is instructed by 2-bit signaling in
downlink control information (DCI). This 2-bit signaling is called
comb instruction signaling, and a comb instruction signaling and
comb mapping relationship is as shown in Table 6. The UE determines
the comb to be used by the UE by receiving comb instruction
signaling directly.
TABLE-US-00006 TABLE 6 Table 6: comb instruction signaling and comb
mapping relationship comb instruction signaling value 00 01 10 11
Comb 0 1 2 3
[0090] Or, for example, the UE determines that the repetition
factor (RPF) to be used for DMRSs is 4, that the number of combs to
be used by the DMRSs of the UE is 2, and that a set of combs to be
used by the UE is {0, 2} by receiving higher layer signaling or by
a protocol. Then higher layer signaling (including system
information or UE-specific higher layer signaling) or physical
layer signaling instructs a comb to be used by a DMRS of the UE.
When the comb equals to 0, subcarriers occupied by the UE are
subcarriers, intervals between which is 4, of the PRBs allocated
for PUSCH of the UE, and a start subcarrier of the DMRS is the
start subcarrier of the PRBs allocated for PUSCH of the UE. When
the comb equals to 2, the subcarriers occupied by the UE are
subcarriers, an interval between which is 4, of PRBs allocated for
PUSCH of the UE, and the start subcarrier of the DMRS is the start
subcarrier of the PRBs allocated for PUSCH of the UE plus 2.
[0091] When the comb to be used by the UE is instructed by physical
layer signaling, 1-bit signaling in downlink control information
(DCI) will instruct the comb, this 1-bit signaling is called comb
instruction signaling, and a comb instruction signaling and comb
mapping relationship is as shown in Table 7. The UE determines a
comb to be used by the UE by receiving comb instruction
signaling.
TABLE-US-00007 TABLE 7 Table 7: comb instruction signaling and comb
mapping relationship comb instruction signaling value 0 1 comb 0
2
[0092] When the number of combs to be used for the DMRSs is other
numbers, a similar method may be used to determine a set of combs
first, and then instruct a comb by comb instruction signaling in
DCI.
[0093] Or the comb is determined related to the number of PRBs
allocated for PUSCH of the UE. For example, a set of PRB numbers
allocated possibly for PUSCH of the UE is determined by higher
layer signaling (including system information or UE-specific higher
layer signaling) or by a protocol (for example, the PRB numbers
allocated possibly by the UE is 1, 2, 4, and 8), then a comb is
determined for a PUSCH demodulation reference signal of each PRB
number, for example, determining a comb for a PUSCH demodulation
reference signal of each PRB number in the set of PRB numbers by a
protocol or by higher layer signaling (including system information
or UE-specific higher layer signaling). For example, when the PRB
number that may allocated to the PUSCH of the UE is 1, 2, 4, and 8,
and available combs for DMRSs are 0, 1, 2, and 3, the PRB number
and comb mapping relationship is as shown in Table 8. In this way,
when the number of PRBs of frequency-domain resources allocated to
different UEs for PUSCH are different, and start PRBs of the PUSCH
frequency-domain resources allocated to the UEs are the same, it is
ensured that when the numbers of PRBs of frequency-domain resources
allocated to the UE for PUSCH are different, DMRSs of the UEs are
orthogonal by allocating different combs to the UEs with different
PRB numbers.
TABLE-US-00008 TABLE 8 Table 8: PRB number and comb mapping
relationship PRB number 1 2 4 8 OCC 0 1 2 3
[0094] Then, a method for determining CSs will be described. For
example, when the number of CSs of DMRSs is 8, a CS to be used by a
DMRS of a UE is instructed by higher layer signaling (including
system information or UE-specific higher layer signaling) or
physical layer signaling. When the CS to be used by the DMRS of the
UE is instructed by physical layer signaling, 3-bit signaling in
downlink control information (DCI) will instruct the CS, this 3-bit
signaling is called CS instruction signaling, as shown in Table 9.
The meaning represented by n.sub.DMRS.sup.(2) may be seen in the
version V8.9.0 (2009 December) of 3GPP TS 36.211. Or, when the
number of CSs of the DMRSs is 12, the CS to be used by the DMRS of
the UE is instructed by higher layer signaling (including system
information or UE-specific higher layer signaling) or physical
layer signaling. When the CS to be used by the DMRS of the UE is
instructed by physical layer signaling, 4-bit signaling in downlink
control information (DCI) will instruct the CS, and this 4-bit
signaling is called CS instruction signaling, as shown in Table 10.
The meaning of n.sub.DMRS.sup.(2) may be seen in the version V8.9.0
(2009 December) of 3GPP TS 36.211.
TABLE-US-00009 TABLE 9 Table 9: CS instruction signaling and
n.sub.DMRS.sup.(2) mapping relationship CS instruction signaling
value n.sub.DMRS.sup.(2) 000 0 001 6 010 3 011 4 100 2 101 8 110 10
111 9
TABLE-US-00010 TABLE 10 Table 10: CS instruction signaling and
n.sub.DMRS.sup.(2) mapping relationship CS instruction signaling
value n.sub.DMRS.sup.(2) 0000 0 0001 1 0010 2 0011 3 0100 4 0101 5
0110 6 0111 7 1000 8 1001 9 1010 10 1011 11 1100~1111 Reserved
[0095] When the number of CSs used for the DMRSs is other numbers,
a similar method may be used to determine a set of CSs first, and
then instruct a CS by CS instruction signaling in DCI. The UE
determines the CS by receiving CS instruction signaling.
Method 2:
[0096] First, a UE determines a set of combinations of any two or
three factors of the OCC, CS and comb in a DMRS by being configured
by higher layer signaling or by a protocol, then determines a
combination of OCC, CS and comb from the set of combinations by
being configured by higher layer signaling or by being instructed
by physical layer signaling.
[0097] In the above method 2, the first method for determining the
OCC, CS and comb is that:
[0098] Determining a set of combinations of OCC and comb by being
configured by higher layer signaling or by a protocol, determining
a combination of OCC and comb to be used by a DMRS of the UE from
the set of the combinations of OCC and comb by being configured by
higher layer signaling or by being instructed by physical layer
signaling. A CS to be used by the DMRS of the UE is configured by
higher layer signaling separately, or instructed by physical layer
signaling separately, or determined by a protocol separately, and a
determining method thereof is the same as the method for
determining the CS in the Method 1.
[0099] It is because that when the PUSCH frequency-domain resources
allocated to the UEs overlap incompletely, and DMRSs of different
UEs use different OCCs or combs, the DMRSs of the different UEs are
orthogonal, when the PUSCH frequency-domain resources allocated to
the UEs overlap incompletely, and the DMRSs of the different UEs
use different CSs, the DMRSs of the different UEs are not
orthogonal, and when the PUSCH frequency-domain resources allocated
to the UEs overlap completely, and the DMRSs of different UEs use
different OCCs or combs or CSs, the DMRSs of the different UE are
orthogonal. In this way, when there are PUSCH frequency-domain
resources allocated to multiple UEs, one part of PUSCH
frequency-domain resources allocated to the UEs overlap completely,
and the other part of PUSCH frequency-domain resources allocated to
the UEs overlap incompletely. For DMRSs of UEs, PUSCH
frequency-domain resources allocated to which overlap completely,
the same combination of OCC and comb may be used, and different CSs
may be allocated for DMRSs of different UEs, and in this way, the
DMRSs of the different UEs are orthogonal, for UEs, to which PUSCH
frequency-domain resources allocated overlap incompletely, DMRSs of
different UEs may be allocated with different CSs, and in this way,
the DMRSs of the different UEs are not orthogonal, and the DMRSs of
the UEs may use different combinations of OCC and comb, and in this
way, the DMRSs of the different UEs are orthogonal. A set of OCCs
is {OCC0, . . . , OCCm, . . . , OCCM-1}, where M is the sum of the
set of OCCs, and a set of combs is {comb0, . . . , combn, . . . ,
combN-1}, where N is the sum of the set of combs. And a set of
combinations of OCC and comb is {(OCC0, comb0), . . . , (OCCm,
combn), . . . , (OCCM-1, combN-1)}, where the number of
combinations of OCC and comb is M*N, and the set of combinations of
OCC and comb to be used by the DMRSs of the UEs may be {(OCC0,
comb0), . . . , (OCCm, combn), . . . , (OCCM-1, combN-1)}, or a
subset of it. The sum of the set of OCCs is M, the sum of the set
of combs is N, or the set of combinations of OCC and comb to be
used by the DMRS of the UE is determined by a protocol, or
configured by higher layer signaling. When the sum M of the set of
OCCs, the sum N of the set of combs, or the set of combinations of
OCC and comb to be used by the DMRSs of the UEs is configured by a
protocol or higher layer signaling or physical layer signaling.
[0100] For example, a UE determines that a set of OCCs is {[1 1],
[1 -1]}, a set of combs is {0, 1}, and a set of combinations of OCC
and comb is as shown in Table 11 by receiving higher layer
signaling or by a protocol. Or, the UE determines that a set of
OCCs is {[1 1], [1 -1]}, a set of combs is {0, 1, 2, 3}, and a set
of combination of OCC and combs is as shown in Table 12 by
receiving higher layer signaling or by a protocol. In this way,
since the set of combinations of OCC and comb is obtained, a
specific combination of OCC and comb to be used by a DMRS of the UE
will be configured by higher layer signaling or instructed by
physical layer signaling. When the specific combination of OCC and
comb is instructed by physical layer signaling, it may be
instructed by instruction signaling of the combination of OCC and
comb in uplink DCI, and when there are 4 combinations of OCC and
comb in the set of combinations of OCC and comb, they may be
instructed by 2-bit instruction signaling of the combination of OCC
and comb, and a specific instructing method is as shown in Table
13. The UE determines a combination of OCC and comb to be used by a
DMRS of the UE by receiving instruction signaling of the
combination of OCC and comb, when there are 8 combinations of OCC
and comb in the set of combinations of OCC and comb, they are
instructed by a 3-bit instruction signaling of the combination OCC
and comb. A specific instructing method is as shown in Table 14.
The UE obtains a combination of OCC and comb to be used by the DMRS
of the UE by receiving instruction signaling of the combination of
OCC and comb.
TABLE-US-00011 TABLE 11 Table 11: combination of OCC and comb
combination index of OCC and comb comb OCC 0 0 [1 1] 1 1 [1 -1] 2 0
[1 1] 3 1 [1 -1]
TABLE-US-00012 TABLE 12 Table 12: combination of OCC and comb
combination of OCC and comb comb OCC 0 0 [1 1] 1 1 [1 -1] 2 2 [1 1]
3 3 [1 -1] 4 0 [1 1] 5 1 [1 -1] 6 2 [1 1] 7 3 [1 -1]
TABLE-US-00013 TABLE 13 Table 13: combination of OCC and comb and
combination of OCC and comb instruction signaling value mapping
relationship combination of OCC and comb instruction signaling
value comb OCC 00 0 [1 1] 01 1 [1 -1] 10 0 [1 1] 11 1 [1 -1]
TABLE-US-00014 TABLE 14 Table 14: combination of OCC and comb and
combination of OCC and comb instruction signaling value mapping
relationship combination of OCC and comb comb OCC 000 0 [1 1] 001 1
[1 -1] 010 2 [1 1] 011 3 [1 -1] 100 0 [1 1] 101 1 [1 -1] 110 2 [1
1] 111 3 [1 -1]
[0101] Or, a UE determines, by receiving higher layer signaling or
by a protocol, that a set of OCCs is {[1 1], [1 -1]}, a set of
combs is {0,1,2,3}, and a set of OCCs possibly to be used by DMRSs
of the UE is {[1 1], [1 -1]}, a set of combs possibly to be used by
the DMRSs of the UE is {0,2} and a set of combinations of OCC and
comb possibly to be used by the DMRS of the UE is as shown in Table
15. In this way, after the set of combinations of OCC and comb
possibly to be used by the DMRSs of the UE is obtained, a specific
combination of OCC and comb to be used by the DMRSs of the UE will
be instructed by higher layer signaling or physical layer
signaling. When the specific combination of OCC and comb is
instructed by physical layer signaling, it may be instructed by
instruction signaling of the combination of OCC and comb in uplink
DCI, and when there are 4 combinations of OCC and comb in the set
of combinations of OCC and comb possibly to be used by the DMRSs of
the UE, they are instructed by 2-bit instruction signaling of the
combination of OCC and comb, a specific instructing method is as
shown in Table 16. The UE obtains a combination of OCC and comb to
be used by the DMRS of the UE by receiving instruction signaling of
the combination of OCC and comb.
TABLE-US-00015 TABLE 15 Table 15: combination of OCC and comb
combination of OCC and comb comb OCC 0 0 [1 1] 1 2 [1 -1] 2 0 [1 1]
3 2 [1 -1]
TABLE-US-00016 TABLE 16 Table 16: combination of OCC and comb and
combination of OCC and comb instruction signaling value mapping
relationship combination of OCC and comb comb OCC 00 0 [1 1] 01 2
[1 -1] 10 0 [1 1] 11 2 [1 -1]
[0102] In the above method 2, the second method for determining
OCC, CS and comb is that determining a set of combinations of OCC,
comb, and CS by being configured by higher layer signaling or by a
protocol, determining a combination of OCC, comb, and CS to be used
by the DMRS of the UE from the set of the combinations of OCC,
comb, and CS by being configured by higher layer signaling or
instructed by physical layer signaling.
[0103] For example, the UE determines, by receiving higher layer
signaling or by a protocol, that the set of OCCs is {OCC0, . . . ,
OCCm, . . . , OCCM-1}, where M is the sum of the set of OCCs, the
set of combs is {comb0, . . . , combn, . . . , combN-1}, where N is
the sum of the set of combs, and the set of CSs is as shown in
Table 9 or 10, or the CS number is other numbers beyond the CS
number in Table 9 or 10, then the set of CSs is {CS0, . . . , CSq,
. . . , CSQ-1}, where Q is the sum of the set of CSs. In the
following, the set of combinations of OCC, comb, and CS will be
described.
[0104] A) a method for determining the set of combinations of OCC,
CS and comb is that the number of combinations in the set of
combinations of the 3 factors: OCC, CS and comb is M*N*Q, and the
set of combinations of the 3 factors is {(OCC0, comb0, CS0), . . .
, (OCCm, combn, CSq), . . . , (OCCM-1, combN-1, CSQ-1)}. If the UE
obtains a combination of OCC, CS and comb to be used by the DMRS of
the UE by receiving physical layer signaling instruction, the UE
obtains the combination of OCC, CS and comb to be used by the DMRS
of the UE by receiving a combination of OCC, comb, and CS
instruction signaling in uplink DCI. The number of bits used for
instruction signaling of the combination of OCC, comb, and CS may
be [log 2(M*N*Q)]. For example, M equals to 2, the set of OCCs is
{[1 1], [1 -1]}, N equals to 2, the set of combs is {0, 1}, Q
equals to 4, and the set of CSs is {0, 3, 6, 9}. When the number of
bits used for instruction signaling of the combination of OCC,
comb, and CS is: [log 2(2*2*4)]=4, a mapping relationship of
instruction signaling values of the combination of OCC, comb, and
CS and combinations of OCC, comb, and CS is as shown in Table 17. A
combination of OCC, comb, and CS to be used by the DMRS of the UE
is obtained by receiving instruction signaling of the combination
of OCC, comb, and CS.
TABLE-US-00017 TABLE 17 Table 17: combination of OCC, comb, and CS
and instruction signaling of the combination of OCC, comb, and CS
mapping relationship combination of OCC, comb, and CS instruction
signaling value OCC comb CS 0000 [1 1] 0 0 0001 [1 -1] 0 0 0010 [1
1] 1 0 0011 [1 -1] 1 0 0100 [1 1] 0 3 0101 [1 -1] 0 3 0110 [1 1] 1
3 0111 [1 -1] 1 3 1000 [1 1] 0 6 1001 [1 -1] 0 6 1010 [1 1] 1 6
1011 [1 -1] 1 6 1100 [1 1] 0 9 1101 [1 -1] 0 9 1110 [1 1] 1 9 1111
[1 -1] 1 9
[0105] Or, for example, M equals to 2, the set of OCCs is {[1 1],
[1 -1]}, N equals to 4, the set of combs is {0,1,2,3}, Q equals to
4, and the set of CSs is {0,3,6,9}. The number of bits used for
instruction signaling of the combination of OCC, comb, and CS may
be [log 2(2*4*4)]=5, then a mapping relationship between the
instruction signaling values of the combination of OCC, comb, and
CS and combinations of OCC, comb, and CS is as shown in Table 18.
The combination of OCC, comb, and CS to be used by the DMRS of the
UE will be obtained by receiving instruction signaling of the
combination of OCC, comb, and CS.
TABLE-US-00018 TABLE 18 Table 18: combination of OCC, comb, and CS
and instruction signaling value of the combination of OCC, comb,
and CSs mapping relationship combination of OCC, comb, and CS
instruction signaling value OCC comb CS 00000 [1 1] 0 0 00001 [1
-1] 0 0 00010 [1 1] 1 0 00011 [1 -1] 1 0 00100 [1 1] 0 3 00101 [1
-1] 0 3 00110 [1 1] 1 3 00111 [1 -1] 1 3 01000 [1 1] 0 6 01001 [1
-1] 0 6 01010 [1 1] 1 6 01011 [1 -1] 1 6 01100 [1 1] 0 9 01101 [1
-1] 0 9 01110 [1 1] 1 9 01111 [1 -1] 1 9 10000 [1 1] 2 0 10001 [1
-1] 2 0 10010 [1 1] 3 0 10011 [1 -1] 3 0 10100 [1 1] 2 3 10101 [1
-1] 2 3 10110 [1 1] 3 3 10111 [1 -1] 3 3 11000 [1 1] 2 6 11001 [1
-1] 2 6 11010 [1 1] 3 6 11011 [1 -1] 3 6 11100 [1 1] 2 9 11101 [1
-1] 2 9 11110 [1 1] 3 9 11111 [1 -1] 3 9
[0106] B) Another method for determining the set of combinations of
OCC, CS and comb is that:
[0107] The UE determines, by receiving higher layer signaling or
according to a protocol, that the set of OCCs is {OCC0, . . . ,
OCCm, . . . , OCCM-1}, where M is the sum of the set of OCCs, and
the set of combs is {comb0, . . . , combn, . . . , combN-1}, where
N is the sum of the set of combs, and the set of CSs is as shown in
Table 9 or 10, or the CS number is other CS numbers than those in
Table 9 or 10, then the set of CSs is {CS0, . . . , CSq, . . . ,
CSQ-1}, where Q is the sum of the set of CSs. The maximum possible
number of combinations of the set of OCCs, the set of combs and the
set of combs is M*N*Q. Since the number of supported multiplexing
PUSCH users may be less than M*N*Q, then M*N*Q DMRSs will not be
required, and therefore, part of combinations may be used to be
selected from the M*N*Q combinations of OCC, comb, and CS to form a
set, and the set is a subset of the set {(OCC0, comb0, CS0), . . .
, (OCCm, combn, CSq), . . . , (OCCM-1, combN-1, CSQ-1)}, and the UE
determines, by receiving higher layer signaling or according to a
protocol, a subset of the set of combinations of OCC, comb and CS,
in which the number of combinations of OCC, CS and comb in the
subset is L, then determines a combination of OCC, comb, and CS to
be used by the DMRS of the UE from the subset of the set of the
combinations of OCC, comb and CS, and the number of bits used for
instruction signaling of the combination of OCC, comb, and CS may
be a ceiling value of [log 2(L)]. The UE obtains a combination of
OCC, comb, and CS to be used by the DMRS of the UE by receiving
instruction signaling of the combination of OCC, comb, and CS.
[0108] For example, M equals to 2, the set of OCCs is {[1 1], [1
-1]}, N equals to 2, the set of combs is {0, 1}, Q equals to 4, and
the set of CSs is {0, 3, 6, 9}. According to the maximum possible
number of combinations of the set of OCCs, the set of combs and the
set of combs being 2*2*4=16, the number L of the DMRSs currently
used is determined, i.e., the actual number of DMRSs used L=8, then
8 of the 16 combinations of OCC, comb, and CS are selected, and the
number of bits used for instruction signaling of the combinations
of OCC, comb, and CS may be [log 2(8)]=3. Assume that a mapping
relationship between instruction signaling values of the
combinations of OCC, comb, and CS and selected combinations of OCC,
comb, and CS is as shown in Table 19. The UE obtains a combination
of OCC, comb, and CS to be used by the DMRS of the UE by receiving
instruction signaling of a combination of OCC, comb, and CS.
TABLE-US-00019 TABLE 19 Table 19: combination of OCC, comb, and CS
and instruction signaling value of the combination of OCC, comb,
and CS mapping relationship instruction signaling value of
combination of OCC, comb and CS OCC comb CS 000 [1 1] 0 0 001 [1
-1] 0 0 010 [1 1] 1 3 011 [1 -1] 1 3 100 [1 1] 0 6 101 [1 -1] 0 6
110 [1 1] 1 9 111 [1 -1] 1 9
[0109] Or, for example, M equals to 2, the set of OCCs is {[1 1],
[1 -1]}, N equals to 2, the set of combs is {0,1}, Q equals to 8,
and the set of CSs is {0,2,3,4,6,8,9,10}. The maximum possible
number of combinations of the set of OCCs, the set of combs and the
set of combs is 2*2*8=32, but the number of DMRSs actually used is
8, then 8 out of 32 combinations of OCC, comb, and CS will be
selected, and the number of bits used for instruction signaling of
the combinations of OCC, comb, and CS is [log 2(8)]=3. Assume that
a mapping relationship between instruction signaling values of the
combinations of OCC, comb, and CS and the selected combinations of
OCC, comb, and CS is as shown in Table 20. The UE obtains a
combination of OCC, comb, and CS to be used by the DMRS of the UE
by receiving instruction signaling of the combination of OCC, comb,
and CS.
TABLE-US-00020 TABLE 20 Table 20: combination of OCC, comb, and CS
and instruction signaling value of the combination of OCC, comb,
and CS mapping relationship combination of OCC, comb, and CS
instruction signaling value OCC comb CS 000 [1 1] 0 0 001 [1 -1] 0
3 010 [1 1] 1 2 011 [1 -1] 1 8 100 [1 1] 0 6 101 [1 -1] 0 9 110 [1
1] 1 4 111 [1 -1] 1 10
[0110] Or, for example, M equals to 2, the set of OCCs is {[1 1],
[1 -1]}, N equals to 2, the set of combs is {0,1}, Q equals to 8,
and the set of CSs is {0,2,3,4,6,8,9,10}. Assuming that the maximum
possible number of combinations of the set of OCCs, the set of
combs and the set of combs is 2*2*8=32, and the number of DMRSs
actually used is 16, then 16 of the 32 combinations of OCC, comb,
and CS will be selected, and the number of bits used for
instruction signaling of the combination of OCC, comb, and CS is
[log 2(16)]=4. Assume that a mapping relation between instruction
signaling values of the combinations of OCC, comb, and CS and the
selected combinations of OCC, comb, and CS is as shown in Table 21.
The UE obtains a combination of OCC, comb, and CS to be used by the
DMRS of the UE by receiving instruction signaling of the
combination of OCC, comb, and CS.
TABLE-US-00021 TABLE 21 Table 21: combination of OCC, comb, and CS
and instruction signaling value of the combination of OCC, comb,
and CS mapping relationship combination of OCC, comb, and CS
instruction signaling value OCC comb CS 0000 [1 1] 0 0 0001 [1 -1]
0 2 0010 [1 1] 1 0 0011 [1 -1] 1 2 0100 [1 1] 0 6 0101 [1 -1] 0 8
0110 [1 1] 1 6 0111 [1 -1] 1 8 1000 [1 1] 0 3 1001 [1 -1] 0 4 1010
[1 1] 1 3 1011 [1 -1] 1 4 1100 [1 1] 0 9 1101 [1 -1] 0 10 1110 [1
1] 1 9 1111 [1 -1] 1 10
[0111] A principle of selecting the combination of OCC, CS and comb
from the possible combinations of the set of OCCs, the set of combs
and the set of combs is first, the selected different combinations
of OCC, CS and comb should ensure that when the PUSCH
frequency-domain resources allocated to the UEs overlap
incompletely, the number of DMRSs that are still orthogonal is the
maximum. As shown in Table 21, since the number of OCCs in the set
of OCCs is 2, and the number of combs in the set of combs is 2,
then when the PUSCH frequency-domain resources allocated to the UEs
overlap incompletely, there will be 4 orthogonal DMRSs to the
maximum in each subset, which are DMRSs generated from a subset of
the four combinations of OCC, comb and CS, instruction signaling
values of the combinations of OCC, comb, and CS are
{0000,0001,0010,0011}, and DMRSs generated from a subset of the
four combinations of OCC, comb, and CS, instruction signaling
values of the combinations of OCC, comb, and CS are
{0100,0101,0110,0111}, and DMRSs generated from a subset of the
four combinations of OCC, comb, and CS, instruction signaling
values of the combinations of OCC, comb, and CS are
{1000,1001,1010,1011}, and DMRSs generated from a subset of the
four combinations of OCC, comb and CS, instruction signaling values
of the combinations of OCC, comb, and CS are{1100,1101,1110,1111}.
For combinations where OCCs and combs are same, but CSs are
different, they are not orthogonal when the PUSCH frequency-domain
resources allocated to the UEs overlap incompletely, and they are
orthogonal when the PUSCH frequency-domain resources allocated to
the UEs overlap completely, so that the greater the interval
between their CSs is, the less is affected by interference of
orthogonality between them. For example, OCCs and combs of four
combinations of OCC, comb, and CS, of which instruction signaling
values of the combinations of OCC, comb, and CS are
{0000,0100,1000,1100} are the same, the maximum interval between
their CSs is {0,6,3,9} respectively.
Embodiment 2
[0112] In this embodiment 2, a method for transmitting demodulation
reference signals in case of a PUSCH without control signaling
scheduling (Grant-less) will be described.
[0113] There are two situations for UEs to select resources. A
situation is that the number of PRBs of frequency-domain resources
selected by the UEs to transmit PUSCHs is related to the positions
of the frequency-domain resources, e.g., the number of PRBs that
the UEs use at different positions of the frequency-domain
resources are different. In this way, either the frequency-domain
resources used by the UEs for transmitting the PUSCHs overlap
completely, or the frequency-domain resources used by the UEs for
transmitting the PUSCHs do not overlap at all. As shown in FIG. 8,
the frequency-domain resources of the numbers of PRBs being 1, 2,
and 4 for transmitting PUSCHs do not overlap at all. In this
situation, as long as one of the three factors, OCC, DMRS comb or
CS of DMRS, is different, DMRSs are orthogonal. Another situation
is that the numbers of PRBs of the frequency-domain resources for
transmitting PUSCHs allocated to the UEs are independent of the
positions of the frequency-domain resources, e.g., the numbers of
PRBs that the UEs use at the same position of the frequency-domain
resources may be same or different. In this way, the
frequency-domain resources used by the UEs for transmitting PUSCHs
may overlap completely, or the frequency-domain resources used by
the UEs for transmitting the PUSCHs may overlap incompletely. In
this situation, as long as one of the two factors, the DMRS OCC and
DMRS comb, is different, DMRSs are orthogonal, but when the CSs of
DMRSs are different, DMRSs may or may not be orthogonal.
[0114] Since a PUSCH is not scheduled by DCI in this case, it is
the UE that decides whether to transmit the PUSCH or not, and
parameters of the UE for transmitting the PUSCH is configured by
higher layer signaling or selected independently by the UE, and
therefore, it cannot be instructed by physical layer signaling,
i.e., the OCC, and/or comb and/or CS to be used by the DMRS of the
UE is instructed by instruction signaling in DCI.
[0115] First, the number of the OCCs of the DMRS is M (M is a
positive integer larger than or equal to 1, and it is configured by
higher layer signaling (including system information or UE-specific
higher layer signaling), or determined by a protocol, e.g., M=1, 2,
4, 8, and the like), and the set of OCCs is {OCC0, . . . , OCCm, .
. . , OCCM-1 }, and it is determined by a protocol. The number of
combs of the DMRS is N (N is a positive integer larger than or
equal to 1, and it is configured by higher layer signaling
(including system information or UE-specific higher layer
signaling), or determined by a protocol, e.g., N=1, 2, 4, 8, and
the like), and the set of combs is {comb0, . . . , combn, . . . ,
combN-1}, and it is determined by a protocol. The number of the CSs
of the DMRS is q (q is a positive integer larger than or equal to
1, and it is configured by higher layer signaling (including system
information or UE-specific higher layer signaling), or determined
by a protocol, e.g., q=1, 2, 4, 8, 12, and the like), and the set
of CSs is as shown in Table 7 or Table 8, or determined by a
protocol.
[0116] In the following, several methods for transmitting DMRSs
will be described.
Method 1:
[0117] A UE determines an OCC, and/or a CS, and/or a comb to be
used by a DMRS of the UE by receiving higher layer signaling
(including system information or UE-specific higher layer
signaling) configuration, or by a protocol.
[0118] Specifically, the following three methods may be
included:
[0119] The first method is that the UE determines a candidate set
from a set of OCCs, a set of CSs and a set of combs to be used by a
DMRS of the UE by receiving higher layer signaling (including
system information or UE-specific higher layer signaling) or by a
protocol first. Then the UE determines the OCC to be used from the
set of OCCs, and/or determines the CS to be used from the set of
CSs, and/or determines the comb to be used from the set of the
combs by being configured by higher layer signaling or by
independent selection of the UE.
[0120] The second method is that the UE determines the combination
of OCC, and/or CS, and/or comb to be used by the DMRS of the UE by
receiving higher layer signaling (including system information or
UE-specific higher layer signaling).
[0121] In the following, how to determine a specific combination of
OCC, and/or CS, and/or comb to be used by the DMRS of the UE from
the set of OCCs, the set of CSs and the set of combs will be
described.
[0122] First, a method for determining an OCC of the DMRS will be
described, where the set of OCCs is {OCC0, . . . , OCCm, . . . ,
OCCM-1}. For example, when the UE determines that the number of
SC-FDMA or OFDM symbols for the DMRS is 2 by receiving higher layer
signaling or according to a protocol, the number of the OCCs is 2,
and the set of OCCs to be used by the UE is {[w(0) w(1)]=[1 1],
[w(0) w(1)]=[1 -1]}, then the OCC to be used by the DMRS of the UE
is determined by higher layer signaling or by independent selection
of UE.
[0123] Or, for example, when the UE determines that the number of
SC-FDMA or OFDM symbols to be used for the DMRS is 4, the number of
OCCs is 4, and the set of OCC [w(0) w(1) w(2) w(3)] to be used by
the DMRS of the UE is {[1 1 1 1], [1 1 -1 -1], [1 -1 -1 1], [1 -1 1
-1]} by receiving higher layer signaling or according to a
protocol, the OCC to be used by the DMRS of the UE is instructed by
higher layer signaling or selected initiatively by the UE.
[0124] Or, for example, when the UE determines that the number of
SC-FDMA or OFDM symbols used for the DMRS is 4 by receiving higher
layer signaling or according to a protocol, then the possible
number of OCCs is 4. But when the UE determines that the number of
OCCs possibly to be used by the UE is 2 and the set of OCCs [w(0)
w(1) w(2) w(3)] to be used by the DMRS of the UE is {[1 1 1], [1 1
-1 -1]} by receiving higher layer signaling, the OCC to be used for
the DMRS of the UE is configured by higher layer signaling or
selected initiatively by the UE.
[0125] When the number of OCCs in the set of OCCs to be used for
the DMRS are other numbers, a similar method may be used to
determine the set of OCCs first, then an OCC to be used by the DMRS
of the UE is configured by higher layer signaling (including system
information or UE-specific higher layer signaling), or selected
initiatively by the UE.
[0126] Or the OCC is determined related to the number of PRBs for
transmitting a PUSCH selected by the UE. For example, a set of PRB
numbers that the UE may select for transmitting PUSCHs may be
determined by higher layer signaling (including system information
or UE-specific higher layer signaling) or by a protocol (for
example, the PRB numbers allocated that are possibly selected by
the UE are 1, 2, 4, and 8), then an OCC is determined for PUSCH
demodulation reference signal of each PRB number, for example,
determining the OCC for PUSCH demodulation reference signal of each
PRB number in the set of PRB numbers by a protocol or by higher
layer signaling (including system information or UE-specific higher
layer signaling). For example, when the PRB numbers allocated
possibly by the UE are 1, 2, 4, and 8, and available OCCs are {[1 1
1 1], [1 1 -1 -1], [1 -1 -1 1], [1 -1 1 -1]}, a mapping
relationship between PRB numbers and OCCs is as shown in Table 4.
In this way, when the PRB numbers of PUSCH frequency-domain
resources selected by UEs are different, and start PRBs of the
PUSCH frequency-domain resources selected by UE are the same, it is
ensured that when the PRB numbers of PUSCH frequency-domain
resources allocated to the UEs are different, their DMRSs are
orthogonal by selecting different OCCs for the UEs that select
different PRB numbers. When the PRB numbers of PUSCH
frequency-domain resources selected by the UEs are the same, and
the start PRBs of PUSCH frequency-domain resources selected by the
UEs are the same, a same OCC may be selected for the DMRSs of the
UEs and then the UEs may select CSs randomly, and if the CSs
selected by the UEs are different, the DMRS of the UE are
orthogonal.
[0127] Then, a method for determining combs will be described, in
which the set of combs is {comb0, . . . , combn, . . . , combN-1}.
For example, the UE determines that the number of combs to be used
for the DMRS is 2, and a set of combs to be used by the UE is {0,
1} by receiving higher layer signaling or by a protocol, then, a
comb to be used by the DMRS of the UE may be determined by higher
layer signaling (including system information or UE-specific higher
layer signaling) or selected initiatively by the UE. For example,
when a repetition factor (RPF) of DMRSs is 2, there are two combs,
i.e., 0 and 1, and a comb to be used by the DMRS of the UE is
configured by higher layer signaling (including system information
or UE-specific higher layer signaling) or selected initiatively by
the UE. When the comb equals to 0, subcarriers occupied by the DMRS
of the UE are subcarriers for transmitting PUSCH on PRBs selected
by the UE, a PRB interval of which is 2, and a start subcarrier of
the DMRS is a start subcarrier of PRBs for transmitting PUSCH
selected by the UE, and when the comb equals to 1, subcarriers
occupied by the DMRS of the UE are subcarriers for transmitting
PUSCH on PRBs selected by the UE, a PRB interval of which is 2, and
a start subcarrier of the DMRS is the start subcarrier of the PRBs
for transmitting PUSCH selected by the UE plus 1.
[0128] Or, for example, when the UE determines that the number of
combs used as the DMRS is 4 and a set of combs to be used by the UE
is {0, 1, 2, 3} by receiving higher layer signaling or by a
protocol, then, a comb to be used by the DMRS of the UE is selected
according to higher layer signaling (including system information
or UE-specific higher layer signaling) or initiative selection by
the UE. When the comb equals to 0, subcarriers occupied by the DMRS
of the UE are subcarriers of PRBs for transmitting the PUSCH
selected by the UE, an interval between which is 4, and a start
subcarrier of the DMRS is the start subcarrier of the PRBs for
transmitting PUSCH selected by the UE, and when the comb equals to
1, subcarriers occupied by the DMRS of the UE are subcarriers of
PRBs for transmitting the PUSCH selected by the UE, an interval
between which is 4, and a start subcarrier of the DMRS is the start
subcarrier of the PRBs for transmitting PUSCH selected by the UE
plus 1, when the comb equals to 2, subcarriers occupied by the DMRS
of the UE are subcarriers of PRBs for transmitting PUSCH selected
by the UE, an interval between which is 4, and a start subcarrier
of the DMRS is the start subcarrier of the PRBs for transmitting
PUSCH selected by the UE plus 2, and when the comb equals to 3,
subcarriers occupied by the DMRS of the UE are subcarriers of PRBs
for transmitting PUSCH selected by UE, an interval between which is
4, and a start subcarrier of the DMRS is the start subcarrier of
the PRBs for transmitting PUSCH selected by the UE plus 3.
[0129] Or, for example, the UE determines that the repetition
factor (RPF) for the DMRS is 4, the number of combs to be used by
the DMRS of the UE is 2, and a set of combs to be used by the DMRS
of the UE is {0,2} by receiving higher layer signaling or by
protocol, then, a comb to be used by the DMRS of the UE is selected
by higher layer signaling (including system information or
UE-specific higher layer signaling) or selected initiatively by the
UE. When the comb equals to 0, subcarriers occupied by the DMRS of
the UE are subcarriers of PRBs for transmitting PUSCH selected by
the UE, an interval between which is 4, and a start subcarrier of
the DMRS is the start subcarrier of the PRBs for transmitting PUSCH
selected by the UE, and when the comb equals to 2, subcarriers
occupied by the DMRS of the UE are subcarriers of the PRBs for
transmitting PUSCH selected by the UE, an interval between which is
4, and a start subcarrier of the DMRS is the start subcarrier of
the PRBs for transmitting PUSCH selected by the UE plus 2.
[0130] When the number of combs used for the DMRS is other numbers,
a similar method may be used to determine a set of combs first,
then a comb to be used by the DMRS of the UE is determined by
higher layer signaling or selected initiatively by the UE.
[0131] Or a comb to be used by the DMRS of the UE is determined
related to the number of PRBs for transmitting a PUSCH selected by
the UE. For example, a set of PRB numbers that may be selected by
the UE for transmitting the PUSCH is determined according to higher
layer signaling (including system information or UE-specific higher
layer signaling) or by a protocol (for example, the PRB numbers
that may be selected for transmitting PUSCH may be 1, 2, 4, and 8),
then the UE determines a comb according to a PUSCH demodulation
reference signal of a PRB number for transmitting the PUSCH. For
example, the UE determines a comb of a PUSCH demodulation reference
signal of each PRB number in the set of PRB numbers according to a
protocol or higher layer signaling (including system information or
UE-specific higher layer signaling). For example, when the PRB
numbers that the UE may select for transmitting the PUSCH are 1, 2,
4, and 8, and available combs are 0, 1, 2, and 3, a mapping
relationship between the PRB numbers and combs is shown in Table 8.
allocated In this way, if the PRB numbers of PUSCH frequency-domain
resources selected by UEs are different, and start PRBs of PUSCH
frequency-domain resources selected by the UEs are the same, it is
ensured that by selecting different combs in case of different PRB
numbers, it is ensured that when the PRB numbers of PUSCH
frequency-domain resources allocated to the UEs are different,
DMRSs of the UEs are orthogonal.
[0132] Then, a method of determining CSs will be described. For
example, when the number of CSs of the DMRS is 8, the CSs to be
used by the DMRS of the UE are configured by higher layer signaling
(including system information or UE-specific higher layer
signaling), or selected initiatively by the UE. When the number of
CSs to be used for the DMRS are other numbers, a similar method may
be used to first determine a set of CSs first, then configure the
CS to be used by the DMRS of the UE by higher layer signaling, or
select the CS to be used by the DMRS of the UE initiatively by the
UE.
Method 2:
[0133] First, A UE determines a set of combinations of any two or
three factors, i.e., the DMRS OCC, CS and comb, by being configured
by higher layer signaling or by a protocol, then selects a
combination of OCC, CS and comb to be used by the DMRS of the UE
from the set of combinations by being configured by higher layer
signaling or by initiative selection by the UE.
[0134] In the above method 2, the first method for determining OCC,
CS and comb is that determining a set of combinations of OCC and
comb by being configured by higher layer signaling or by a
protocol, and then determining a combination of OCC and comb to be
used by the DMRS of the UE from the set of the combinations of OCC
and comb by being configured by higher layer signaling or by
initiative selection by the UE. The CS to be used by the DMRS of
the UE is configured by higher layer signaling separately, or
selected initiatively by the UE.
[0135] It is because that when the PUSCH frequency-domain resources
selected by UEs overlap incompletely, and when DMRSs of different
UEs may use different OCCs or combs, DMRSs of the different UEs are
orthogonal, when PUSCH frequency-domain resources selected by the
UEs overlap incompletely, and when the DMRSs of different UE use
different CSs, DMRSs of the different UEs are not orthogonal, but
when the PUSCH frequency-domain resources selected by the UEs
overlap completely, and when the DMRSs of the different UEs use
different OCCs, combs or CSs, the DMRSs of the different UEs are
orthogonal. In this way, when there are PUSCH frequency-domain
resources selected by multiple UEs, PUSCH frequency-domain
resources selected by part of UEs overlap completely, and PUSCH
frequency-domain resources allocated to the other part of UEs
overlap incompletely. For UEs, PUSCH frequency-domain resources
selected of which overlap completely, the UEs may use a same
combination of OCC and comb, and different UEs select different
CSs, such that DMRSs of different UEs are orthogonal, for UEs,
PUSCH frequency-domain resources selected of which overlapping
incompletely, different UEs select different CSs, such that DMRSs
of the different UEs are not orthogonal, and the UEs may use
different combinations of OCC and comb, such that DMRSs of
different UEs are orthogonal. A set of OCCs is {OCC0, . . . , OCCm,
. . . , OCCM-1}, where M is the sum of the set of OCCs, a set of
combs is {comb0, . . . , combn, . . . , combN-1}, where N is the
sum of the set of combs, and a set of combinations of OCC and comb
is {(OCC0, comb0), . . . , (OCCm, combn), . . . , (OCCM-1,
combN-1)}, and a set of combinations of OCC and combs to be used by
DMRSs of the UEs may be a set {(OCC0, comb0), . . . , (OCCm,
combn), . . . , (OCCM-1, combN-1)}, or a subset of the set. The sum
of the set of OCCs is M, the sum of the set of combs is N, or the
combinations of OCC and comb to be used by the DMRSs of the UEs are
configured by a protocol or by higher layer signaling. When the sum
M of the set of OCCs, the sum N of the set of combs, or the set of
combinations of OCC and comb to be used by the DMRSs of the UEs are
determined, combinations of OCC and comb to be used by the DMRSs of
the UEs may be determined by higher layer signaling or by
initiative selection by the UEs.
[0136] For example, a UE determines that a set of OCCs is {[1 1],
[1 -1] } that a set of combs is {0, 1}, and that the set of
combinations of OCC and comb is as shown in Table 11 by receiving
higher layer signaling or by a protocol. Or, the UE determines that
the set of OCCs is {[1 1], [1 -1]}, that the set of combs is {0, 1,
2, 3}, and that the set of combinations of OCC and comb is as shown
in Table 12 by receiving higher layer signaling or by a protocol.
In this way, after a set of combinations of OCC and comb is
obtained, a specific combination of OCC and comb to be used by the
DMRS of the UE will be determined by higher layer signaling or by
initiative selection by the UE.
[0137] Or, a UE determines the set of OCCs is {[1 1], [1 -1]}, the
set of combs is {0, 1, 2, 3}, and the set of OCCs possibly to be
used by the UE is {[1 1] [1 -1] }, the UE using possibly set of
combs is {0, 2} by receiving higher layer signaling or by a
protocol, and the set of combinations of OCC and comb is as shown
in Table 15. In this way, after the set of combinations of OCC and
comb is obtained, the specific combination of OCC and comb to be
used by the DMRS of the UE is determined by higher layer signaling
or by initiatively selection by the UE.
[0138] In the above method 2, the second method for determining
OCC, CS and comb is that determining a set of combinations of OCC,
comb, and CS by being configured by higher layer signaling or by a
protocol, and then determining a combination of OCC, comb, and CS
to be used by the DMRS of the UE from the set of the combinations
of OCC, comb, and CS by being configured by higher layer signaling
configuration or by a protocol.
[0139] For example, a UE determines that a set of OCCs is {OCC0, .
. . , OCCm, . . . , OCCM-1}, where M is the sum of the set of OCCs,
and a set of combs is {comb0, . . . , combn, . . . , combN-1},
where N is the sum of the set of combs by receiving higher layer
signaling or by a protocol, and a set of CSs is as shown in Table 9
or 10, or the number of CSs is other numbers than those in Table 9
or 10, then the set of CSs is {CS0, . . . , CSq, . . . , CSQ-1},
where Q is the sum of the set of CSs. In the following, a set of
combinations of OCC, comb, and CS will be described.
[0140] a) A method for determining the set of combinations of OCC,
CS, and comb is that when the number of combinations in the set of
combinations of OCC, CS and comb is M*N*Q, and the set of
combinations of OCC, CS and comb is {(OCC0, comb0, CS0), . . . ,
(OCCm, combn, CSq), . . . , (OCCM-1, combN-1, CSQ-1)}, a
combination of OCC, CS and comb from the set of combinations of
OCC, CS and comb to be used by the DMRS of the UE is configured by
higher layer signaling or selected initiatively by the UE.
[0141] For example, M equals to 2, the set of OCCs is {[1 1], [1
-1]}, N equals to 4, the set of combs is {0,1,2,3}, Q equals to 4,
and the set of CSs is {0,3,6,9}. A combination of OCC, CS and comb
from the set of combinations of OCC, CS and comb to be used by the
UE is configured by higher layer signaling, or selected
initiatively by the UE.
[0142] b) Another method for determining the set of combinations of
OCC, CS and comb is that:
[0143] A UE determines that the set of OCCs is {OCC0, . . . , OCCm,
. . . , OCCM-1}, where M is the sum of the set of OCCs, and the set
of combs is {comb0, . . . , combn, . . . , combN-1}, where N is the
sum of the set of combs by receiving higher layer signaling or by a
protocol, and the set of CSs is as shown in Table 9 or 10, or the
number of CSs is other numbers than those in Table 9 or 10, then
the set of CSs is {CS0, . . . , CSq, . . . , CSQ-1}, where Q is the
sum of the set of CSs. The maximum number of possible combinations
of the set of OCCs, the set of combs and the set of combs is M*N*Q.
Since the number of UEs that support multiplexing PUSCH may be less
than M*N*Q, then M*N*Q DMRSs will not be required, and therefore,
part of combinations are to be selected from the M*N*Q combinations
of OCC, comb, and CS to form a set, and the set is a subset of the
set {(OCC0, comb0, CS0), . . . , (OCCm, combn, CSq), . . . ,
(OCCM-1, combN-1, CSQ-1)}. The UE determines the OCCs, CSs and
combs in the subset of the set of combinations of OCC, CS and comb,
and determines that the number of combinations that can be used by
the DMRS of the UE is L and the combinations of OCC, CS and comb in
the subset of the set of combinations of OCC, CS and comb. Then a
combination of OCC, CS and comb is configured by higher layer
signaling or selected initiatively by the UE from the set of
combinations of OCC, CS and comb to be used by the DMRS of the
UE.
[0144] Or, for example, M equals to 2, the set of OCCs is {[1 1],
[1 -1]}, N equals to 2, the set of combs is {0, 1, 2, 3}, Q equals
to 4, and the set of CSs is {0, 3, 6, 9}. The UE determines an
available set of OCCs to the UE is {[1 1] [1 -1]}, N equals to 2, a
set of combs is {0, 1}, Q equals to 2, and a set of CSs is {0, 6}
by receiving higher layer signaling or by a protocol. Then a
combination of OCC, CS and comb to be used for the UE from the set
of combinations of OCC, CS and comb is configured by higher layer
signaling or selected initiatively by the UE.
[0145] Or, for example, M equals to 2, the set of OCCs is {[1 1],
[1 -1]}, N equals to 2, the set of combs is {0,1}, Q equals to 8,
and the set of CSs is {0,2,3,4,6,8,9,10}. Since the maximum
possible number of combinations of the set of OCCs, the set of
combs and the set of combs is 2*2*8=32, and the number of DMRSs
actually used is 16, then 16 of 32 combinations of OCC, comb, and
CS should be selected. It is determined that M equals to 2, that a
set of OCCs available to the UE is {[1 1], [1 -1]}, that N equals
to 2, that the set of combs is {0, 1}, that Q equals to 4, and the
set of CSs is {0, 3, 6, 9,} by being configured by higher layer
signaling or by a protocol. A combination of OCC, CS and comb from
the set of combinations of OCC, CS and comb to be used by the DMRS
of the UE is configured by higher layer signaling or selected
initiatively by the UE.
[0146] The principle of selecting the combination of OCC, CS and
comb from the possible combinations of the set of OCCs, the set of
combs and the set of combs is that first, the selected different
combinations of OCC, CS and comb should ensure that when the
frequency-domain resources for transmitting PUSCH selected by the
UEs overlap incompletely, the number of DMRSs that are still
orthogonal is the maximum. As shown in Table 16, since the number
of OCCs in the set of OCCs is 2, and the number of combs in the set
of combs is 2, then when the frequency-domain resources for
transmitting PUSCH selected by the UEs overlap incompletely, there
will be 4 orthogonal DMRSs to the maximum in each subset. The 4
orthogonal DMRSs are a DMRS generated from a subset of four
combinations of OCC, comb and CS, instruction signaling values of
the combinations of OCC, comb, and CS are {0000, 0001, 0010, 0011},
a DMRS generated from a subset of four combinations of OCC, comb
and CS, instruction signaling values of the combinations of OCC,
comb, and CS are {0100, 0101, 0110, 0111}, a DMRS generated from a
subset of four combinations of OCC, comb and CS, instruction
signaling values of the combinations of OCC, comb, and CS are
{1000, 1001, 1010, 1011}, and a DMRS generated from a subset of
four combinations of OCC, comb, and CS, instruction signaling
values of the combinations of OCC, comb, and CS are {1100, 1101,
1110, 1111}. For combinations of OCC, comb and CS, in which OCCs
and combs are same but CSs are different, they are not orthogonal
when the frequency-domain resources for transmitting PUSCH selected
by UEs overlap incompletely, and DMRSs of them are orthogonal when
the frequency-domain resources for transmitting PUSCH selected by
UEs overlap completely, so that the greater the interval between
CSs is, the less is affected by the interference of the
orthogonality between them. For example, OCCs and combs of 4
combinations of OCC, comb and CS, instruction signaling values of
which are {0000, 0100, 1000, 1100}, are the same, the maximum
intervals between their CSs are {0, 6, 3, 9} respectively.
Embodiment 3
[0147] In this embodiment 3, a power control method for a DMRS with
comb being introduced will be described. For example, a UE
determines power of transmitting a DMRS according to whether the
DMRS uses a comb and according to a format of the comb.
[0148] In traditional PUSCH power, for a UE, a PUSCH and a DMRS use
the same subcarriers, and transmission power of the PUSCH and power
of the DMRS for demodulating the PUSCH are the same. When the DMRS
with comb is introduced, a PUSCH of a UE is transmitted on all the
subcarriers, but a DMRS of the UE is transmitted on subcarriers
having a RPF interval, and the UE transmits nothing on subcarriers
between the subcarriers for transmitting the DMRS. In this way, if
transmission power of the UE on each DMRS subcarrier and
transmission power on each PUSCH subcarrier are same, then total
transmission power of the UE on all subcarriers of a DMRS SC-FDM or
OFDM symbol is smaller than total transmission power of the UE on
all subcarriers of a PUSCH SC-FDM or OFDM symbol, which means that
power of the UE has been wasted.
[0149] A method for determining DMRS power is that if a UE
transmits a DMRS using a comb format, total power of all
subcarriers that transmit a DMRS within each SC-FDM symbol is the
same with total power of all subcarriers that transmit a PUSCH
within each SC-FDM symbol.
[0150] Another method for determining DMRS power is that if a UE
transmits a DMRS using a comb format, transmission power of the UE
on each DMRS subcarrier and transmission power of the UE on each
PUSCH subcarrier are the same.
[0151] Another method for determining DMRS power is that if a UE
transmits a DMRS using a comb format, power of a DMRS transmitted
on each DMRS subcarrier and power of a PUSCH transmitted on each
PUSCH subcarrier are different, and total transmission power of the
UE on all subcarriers of each DMRS SC-FDM symbol and total
transmission power of the UE on all subcarriers of each PUSCH
SC-FDM symbol are the same, i.e., transmission power of the UE on
each subcarrier of each DMRS SC-FDM symbol is RPF times of
transmission power of the UE on each subcarrier of each PUSCH
SC-FDM symbol, PDMRS=RPF*PPUSCH, or transmission power of the UE on
each subcarrier of each DMRS SC-FDM symbol is
PDMRS=min{RPF*PPUSCH,P1}, where PDMRS is transmission power (dBm)
of the UE on each subcarrier of each DMRS SC-FDM symbol, PPUSCH is
transmission power (dBm) of the UE on each subcarrier of each PUSCH
SC-FDM, and P1 is the allowable maximum difference (configured by
higher layer signaling, or determined by a protocol) between
transmission power of the UE on each subcarrier of each DMRS SC-FDM
and transmission power of the UE on each subcarrier of each PUSCH
SC-FDM. For example, when the RPF equals to 2, the UE transmits a
DMRS on subcarriers, an interval between which is 2, and power of
the DMRS transmitted on each DMRS subcarrier by the UE is 2 times
of power of the PUSCH transmitted on each PUSCH subcarrier by the
UE, i.e., power of a DMRS transmitted on each DMRS subcarrier by
the UE being 3 dB larger than power of a PUSCH transmitted on each
PUSCH subcarrier by the UE. When the RPF equals to 4, the UE
transmits a DMRS on subcarriers, an interval between which is 4,
and power of the DMRS transmitted on each DMRS subcarrier by the UE
is 2 or 4 times of power of the PUSCH transmitted on each PUSCH
subcarrier by the UE, i.e., power of a DMRS transmitted on each
DMRS subcarrier by the UE is 3 dB or 6 dB larger than power of a
PUSCH transmitted on each PUSCH subcarrier by the UE. When the RPF
equals to 8, the UE transmits a DMRS on subcarriers, an interval
between which is 8, and power of the DMRS transmitted on each DMRS
subcarrier by the UE is 2, 4 or 8 times of transmission power of
the PUSCH transmitted on each PUSCH subcarrier by the UE, i.e.,
power of a DMRS transmitted on each DMRS subcarrier by the UE being
3 dB, 6 dB or 9 dB larger than power of a PUSCH transmitted on each
PUSCH subcarrier by the UE. In this way, the difference between
power for transmitting a DMRS on each DMRS subcarrier and power for
transmitting a PUSCH on each PUSCH subcarrier will not be too
large.
Embodiment 4
[0152] In this embodiment 4, a method for generating a DMRS
sequence with a comb being introduced will be described. For
example, a UE determines a DMRS sequence to be transmitted
according to whether the DMRSs uses a comb and according to a
format of the comb. When a DMRS does not use a comb, the number of
subcarriers occupied by the DMRS and the number of subcarriers
occupied by a PUSCH are the same, and therefore, the length of the
DMRS sequence and the number of subcarriers of the PUSCH scheduled
by the UE in the frequency domain are the same. However, when a
DMRS uses a comb, the number of subcarriers used by the UE actually
for transmitting the DMRS in the frequency domain and the number of
subcarriers of the PUSCH scheduled by UE in the frequency domain
are different. Then, the DMRS may be generated as the following
methods.
[0153] The length of a DMRS sequence is in accordance with the
number of subcarriers that the UE actually uses to transmit DMRSs
in the frequency domain, and the DMRS sequence is generated
according to traditional methods. For example, when the number of
subcarriers of a PUSCH scheduled by the UE in the frequency domain
is 48, i.e., 4 PRBs, and a RPF of the DMRS equals to 4, then,
according to the length of the DMRS sequence being equal to 12, the
DMRS sequence is generated according to the method described in the
part 5.5.2 of 3GPP TS36.211, V8.9.0 (December of 2009). When the
number of subcarriers of a PUSCH scheduled by the UE in the
frequency domain is M.sub.SC.sup.PUSCH, and when the DMRS sequence
of the UE uses a comb, the number of subcarriers of the DMRSs
actually transmitted by the UE in the frequency domain equals to
the number of subcarriers of the PUSCH scheduled by UE in the
frequency domain, i.e., M.sub.SC.sup.PUSCH/RFP. At present, since
an elementary unit of a PUSCH scheduled by the UE in the frequency
domain is a PRB, i.e., 12 subcarriers, and therefore, the length of
the DMRS sequence transmitted in the frequency domain is also a
multiple of 12. So, when the number of PRBs of the PUSCH scheduled
by the UE in the frequency domain is not an integer multiple of the
RPF, the number of subcarriers of DMRSs in the frequency domain is
not a multiple of 12, and in this case, there is not an available
DMRS sequence. A method is that, if the number of PRBs of the PUSCH
scheduled by the UE in the frequency domain resources is an
integral multiple M of the RPF, the length of the transmitted DMRS
sequence is M the number of PRBs, i.e., M times of the number of
PRBs, and in this way, it is ensured that there is an available
DMRS sequence. Another method is that, if the number of PRBs of the
PUSCH scheduled by the UE in the frequency-domain resources is not
an integral multiple of the RPF, the UE generates a new DMRS
sequence different from a DMRS sequence in the prior art, and the
new DMRS sequence satisfies the following conditions when PUSCHs
scheduled by UEs in the frequency-domain resources are the same,
and DMRS RPFs are also the same, if CSs of two DMRS sequences are
different, then the two DMRS sequences are orthogonal. Another
method is that, the number of PRBs of the PUSCH in the
frequency-domain resources scheduled by the UE may not be an
integral multiple of the RPF, and the number of the subcarriers of
the PUSCH scheduled by the UE in the frequency-domain resources is
used as the length of the DMRS sequence, and then the DMRS sequence
is punched or truncated according to the length of the DMRS
sequence. A method of punching is that within a range of scheduled
PRBs, the DMRS sequence in the positions of transmitting DMRSs is
transmitted, and the DMRS sequence in other positions is punched,
i.e., the rest of the DMRS sequence being not used for
transmitting. For example, when the RPF equals to 2, even-number
positions in the DMRS sequence are transmitted, and odd-number
positions in the DMRS sequence are not transmitted. A truncation
method is that within the range of the scheduled PRBs, the UE
transmits the DMRS sequence successively on DMRS positions
according to an order and a length of the DMRS sequence, and the
rest of the DMRS sequence is not transmitted. For example, when the
RPF equals to 2, the first half of the DMRS sequence is transmitted
on DMRS positions, and the second half of the DMRS sequence will
not be transmitted.
Embodiment 5
[0154] The number of orthogonal DMRSs can be increase by
introducing a comb. However, according to different channel
conditions and different requirements for the number of orthogonal
DMRSs, for a specific DMRS, the three factors may not be always
included. A DMRS may contain one of the three factors, i.e., the
DMRS only including the OCC factor, or the DMRS only including the
CS factor, or the DMRS only including the comb factor, or a DMRS
may include two of the three factors, i.e., the DMRS including the
OCC and CS factors, or the DMRS including the OCC and comb factors,
or the DMRS containing the comb and CS factors, or a DMRS may
contain all of the three factors, i.e., the DMRS including the OCC,
CS and comb factors.
[0155] A UE may know that how many factors and which factors are
contained in a DMRS of the UE by receiving higher layer signaling
configuration. For example, the UE in a connected state obtains a
DMRS type by receiving higher layer signaling, and the DMRS type
specifies that how many factors and which factors are included in a
DMRS. For example, according to a traditional 3GPP specification,
if higher layer signaling configures Activate-DMRS-with OCC to be
true, then a DMRS includes the CS and OCC factors, and if no higher
layer signaling configures Activate-DMRS-with OCC, then a DMRS only
includes the CS factor. Or how many factors and which factors to be
included in a DMRS of the UE in a default state is determined
according to a protocol, e.g., a DMRS of a PUSCH scheduled by DCI
scrambled with a C-RNTI only including the CS factor. For example,
when the comb factor is introduced, new higher layer signaling
Activate-DMRS-with OCC and comb may be introduced, and if higher
layer signaling configures Activate-DMRS-with OCC and comb to be
true, then a DMRS includes the comb, CS and OCC factors, i.e.,
DMRSs of the UE using different CSs, DMRSs of the UE using
different OCC, and DMRSs of the UE using different combs, if higher
layer signaling configures Activate-DMRS-with OCC to be true, and
no higher layer signaling configures Activate-DMRS-with OCC and
comb to be true, then a DMRS includes the CS and OCC factors, i.e.,
DMRSs of the UE using different CSs, DMRSs of the UE using
different OCCs, and DMRSs of the UE using a subcarrier same with
that of the PUSCH, and if no higher layer signaling configures
Activate-DMRS-with OCC and Activate-DMRS-with OCC and comb to be
true, then a DMRS only includes the CS factor. New higher layer
signaling may be introduced to determine different factors and
different numbers of factors included in a DMRS. Or, new higher
layer signaling Activate-DMRS-with comb is introduced, and if
higher layer signaling configures Activate-DMRS-with comb to be
true, then a DMRS includes the comb and CS factors. For example,
the UE may determine whether the comb factor is introduced into a
DMRS by receiving higher layer signaling. However, when the number
of PRBs included in the PUSCH scheduled by the UE is relatively
few, if a DMRS with a comb being introduced is used, performance of
channel estimation will be poor. For example, when the PUSCH
scheduled by the UE only includes one PRB, and a RPF of a comb of a
DMRS is 4, only three resource elements (REs) are used for a DMRS
during each time slot, and then performance will be poor. In
addition, the shortest length of a traditional DMRS sequence is 12,
i.e., a length of a DMRS sequence where the PUSCH scheduled by the
UE includes one PRB, and a comb is not introduced, and if the PUSCH
scheduled by the UE includes a PRB and the length of a DMRS
sequence with a comb being introduced is 3, there is not an
available sequence yet, and a new sequence is required to be
designed, which is complex to realize using a protocol.
[0156] To avoid this issue, if the UE knows that a DMRS format
includes the comb factor by receiving higher layer signaling, then
the UE may decide whether to use a DMRS with a comb according to
the PUSCH scheduled by the UE, or decide whether to use the DMRS
with the comb and determine a RPF of a comb included in the DMRS
with the comb. In the following, several methods for determining
the DMRS format will be described.
Method 1:
[0157] When the number of PRBs included in the PUSCH scheduled by
the UE is not a multiple of N (N is a positive integer, and it may
be a RPF value of a comb, e.g., 2 or 4), the UE uses a DMRS without
a comb, and if the number of PRBs included in the PUSCH scheduled
by the UE is a multiple of N, the UE uses a DMRS with a comb, where
N is a positive integer, configured by a protocol or higher layer
signaling, e.g., 2 or 4.
Method 2:
[0158] When the number of PRBs included in the PUSCH scheduled by
the UE is not a multiple of N (N is a positive integer, and it may
be a RPF value of a comb, e.g., 2 or 4) and number of REs in
frequency domain is smaller than M (M is an integer, and is preset
or RRC configuration), the UE uses a DMRS without a comb, and if
the number of PRBs included in the PUSCH scheduled by the UE is a
multiple of N, or the number of PRBs contained in the PUSCH
scheduled by the UE being not a multiple of N and number of REs in
frequency domain is equal or larger than M (M is an integer, and is
preset or RRC configuration), the UE uses a DMRS with a comb, where
N is a positive integer, configured by a protocol or higher layer
signaling, e.g., 2 or 4.
Method 3:
[0159] When the number of PRBs included in the PUSCH scheduled by
the UE is not a multiple of N1 (N1 is a positive integer, and it
may be a RPF value of a comb, e.g., 2), the UE uses a DMRS without
a comb, and when the number of PRBs included in the PUSCH scheduled
by the UE is a multiple of N1 but not a multiple of N2 (N2 is a
positive integer, and it may be a RPF value of a comb, e.g., 4),
the UE uses a DMRS containing a comb, the RPF of which is M1 (M1 is
a positive integer, and it may be a RPF value of the comb, e.g.,
2), then the RPF of the comb contained in the DMRS is M1, when the
number of PRBs included in the PUSCH scheduled by the UE is a
multiple of N1 and also a multiple of N2, the UE uses a DMRS
containing a comb, a RPF of which is M2 (M2 is a positive integer,
and may be a RPF value of the comb, e.g., 4), i.e., the RPF of the
comb contained in the DMRS is M2, where N1, N2, M1 and M2 are
positive integer, N2 is a multiple of N1, M2 is a multiple of M1,
configured by a protocol or higher layer signaling, e.g., N1 being
equal to 2, N2 being equal to 4, M1 being equal to 2, and M2 being
equal to 4.
Method 4:
[0160] If the UE knows that a DMRS contains a comb and that a RPF
of the comb is M1 by receiving higher layer signaling, then when
the number of PRBs included in the PUSCH scheduled by the UE is not
a multiple of N1, the UE uses a DMRS without a comb, and when the
number of PRBs included in the PUSCH scheduled by the UE is a
multiple of N1, the UE uses a DMRS which contains a comb, a RPF of
which is M, i.e., the RPF of the comb contained in the DMRS being
M1. For example, N1 is equal to 2, and M1 is equal to 2. N1 and M1
are positive integers, configured by a protocol or higher layer
signaling, e.g., N1 being equal to 2, and M1 being equal to 2.
[0161] If the UE knows that a DMRS contains a comb and that a RPF
of the comb is M2 by receiving higher layer signaling, then when
the number of PRBs included in the PUSCH scheduled by the UE is not
a multiple of N2, the UE uses a DMRS without a comb, and when the
number of PRBs included in the PUSCH scheduled by the UE is a
multiple of N2, the UE uses a DMRS containing a comb, a RPF of
which is M2, i.e., the RPF of the comb contained in the DMRS being
M2. For example, N2 is equal to 4, and M2 is equal to 4. N1, N2, M1
and M2 are positive integers, where N2 is a multiple of N1, and M2
is a multiple of M1, which are configured by a protocol or higher
layer signaling, e.g., N1 being equal to 2, N2 being equal to 4, M1
being equal to 2, and M2 being equal to 4.
Method 5:
[0162] If the UE knows that a DMRS contains the comb factor by
receiving higher layer signaling, the UE may decide whether to use
a DMRS containing a comb and determine a RPF of the comb contained
in the DMRS according to information bit instruction in UL DCI of
the PUSCH scheduled by the UE. Information bit instruction is
called comb instruction information. For example, when 2 bits are
used for comb instruction information, a mapping relationship
between comb instruction information values and definitions thereof
is shown in Table 22. Values of comb when different RPFs are used
are configured by higher layer signaling.
TABLE-US-00022 TABLE 22 Value of Comb Instruction Information
Definition 00 Using a DMRS without a comb 01 Using a DMRS with a
comb, a RPF of which is 2 10 Using a DMRS with a comb, a RPF of
which is 4 11 Reserved
Method 6:
[0163] If the UE knows that a DMRS contains the comb factor by
receiving higher layer signaling, the UE may decide whether to use
a DMRS containing a comb according to information bit instruction
in UL DCI of the PUSCH scheduled by the UE. Information bit
instruction is called comb instruction information. For example,
when the comb uses 1 bit, a mapping relationship between values of
comb instruction information and definitions thereof is shown in
Table 23, and when comb instruction information instructs that a
DMRS containing a comb is not used, a parameter of the DMRS, e.g.,
instruction without comb is used for OCC and CS instruction, and
when comb instruction information instructs using a DMRS containing
a comb, a parameter of the DMRS, e.g., instruction with comb is
used for OCC, CS and comb instruction.
TABLE-US-00023 TABLE 23 Value of Comb Instruction Information
Definition 0 Using DMRS without a comb 1 Using DMRS with a comb
Method 7:
[0164] If the UE knows that a DMRS contains the comb factor by
receiving higher layer signaling and knows a RPF value by receiving
higher layer signaling, then the UE may decide whether to use a
DMRS containing a comb and determine a comb value of the comb
contained in the DMRS according to information bit instruction in
UL DCI of the PUSCH scheduled by the UE. Information bit
instruction is called comb instruction information, e.g., RPF being
equal to 2, a set of combs being {0,1}, comb instruction
information using 2 bits, and a mapping relationship between values
of comb instruction information and definitions thereof is shown in
Table 24.
TABLE-US-00024 TABLE 24 Value of Comb Instruction Definition 00
Using a DMRS without a comb 01 Using a DMRS with a comb, and the
comb being 0 10 Using a DMRS with a comb, and the comb being 1 11
Reserved
[0165] For example, when RFP is 4, a set of comb is {0, 1, 2, 3},
and 3 bits are used for comb instruction information, a mapping
relationship between values of comb instruction information and
definitions thereof is shown in Table 25.
TABLE-US-00025 TABLE 25 Value of Comb Instruction Information
Definition 000 Using a DMRS without a comb 001 Using a DMRS with a
comb, and the comb being 0 010 Using a DMRS with a comb, and the
comb being 1 011 Using a DMRS with a comb, and the comb being 2 100
Using a DMRS with a comb, and the comb being 3 101 Reserved 110
Reserved 111 Reserved
Method 8:
[0166] If the UE knows that a DMRS contains the comb factor by
receiving higher layer signaling, the UE may determine whether to
use a DMRS containing a comb, determine a RPF value in the comb
contained in the DMRS, and comb values when RPF values are
different according to information bit instruction in UL DCI of the
PUSCH scheduled by the UE. Information bit instruction is called
comb instruction information, e.g., RPF being equal to 2, a set of
combs being {0, 1}, and RPF being equal to 4, a set of combs being
{0, 1, 2, 3}.
TABLE-US-00026 TABLE 26 Value of Comb Instruction Information
Definition 000 Using a DMRS without a comb 001 Using a DMRS with a
comb, where a RPF is equal to 2 and the comb is 0 010 Using a DMRS
with a comb, where a RPF is equal to 2 and the comb is 1 011 Using
a DMRS with a comb, where a RPF is equal to 4 and the comb is 0 100
Using a DMRS with a comb, where a RPF is equal to 4 and the comb is
1 101 Using a DMRS with a comb, where a RPF is equal to 4 and the
comb is 2 110 Using a DMRS with a comb, where a RPF is equal to 4
and the comb is 3 111 Reserved
[0167] When the UE knows that a DMRS contains the comb factor by
receiving higher layer signaling, to prevent the foregoing issue
from being generated when the number of PRBs included in the PUSCH
scheduled by the UE is relatively small, the UE uses different CSs
to generate multiple orthogonal DMRSs, the UE may not use CSs to
differentiate DMRSs of different UEs, which can be realized by a
base station.
[0168] In summary, in the uplink demodulation reference signal
format for demodulating the PUSCH determined in the present
disclosure, besides of the CS and/or OCC, the comb may also be
selected. The comb is that DMRSs occupy subcarriers having specific
intervals and the intervals between the occupied subcarriers are
the same, i.e., using a comb format to transmit DMRSs. Demodulation
reference signals with different combs are orthogonal, and when
PUSCH frequency-domain resources allocated to different UEs overlap
completely, demodulation reference signals using different combs of
UEs are orthogonal, and when the PUSCH frequency-domain resources
allocated to the different UEs overlap incompletely, the
demodulation reference signals using different combs are still
orthogonal. When the comb structure is used to transmit DMRSs, on
the one hand, the capacity of the DMRSs can be increased, so that
more UEs can multiplex the uplink physical resources. On the other
hand, when the PUSCH frequency-domain resources allocated to
different UEs overlap incompletely, and the UEs are going to
multiplex the uplink physical resources, DMRSs using different CSs
are not orthogonal, but, DMRSs using different combs are
orthogonal, more UEs can still multiplex the uplink physical
resources. Hence, the present disclosure can increase the number of
DMRSs that keep orthogonal when the PUSCH frequency-domain
resources overlap incompletely, and thus can improve the
multiplexing ratio of the uplink physical resources in a multi-user
scenario.
[0169] Further, the respective function modules in the embodiments
of the present disclosure may be integrated into one processing
unit, or may be each separate physical module. Alternatively, two
or more than two modules may integrate into one unit. The above
integrated unit not only may be implemented with hardware, but also
may be implemented with software function units. The function
modules in the each module may be located at one terminal or
network mode, or may be distributed to multiple terminals or
network modes.
[0170] Further, each embodiment of the present disclosure may be
implemented by data processing applications, which may be executed
by the data processing device, such as a computer. Apparently, the
data processing application may constitute embodiments of the
present disclosure. Further, the data processing application stored
in a storage medium generally may be executed by reading the data
processing application out from the storage medium, and installing
or copying the data processing application to a storage device
(such as hardware or memory) of the data processing device.
Therefore, the storage medium may constitute embodiments of the
present disclosure. The storage medium may adopt any recording
mode, such as a paper storage medium (such as, a paper tape), a
magnetic storage medium (such as, floppy, disk and flash), an
optical storage medium (such as, compact disc read-only memory
(CD-ROM)), and a magneto-optical storage medium (such as
magneto-optical (MO)).
[0171] Therefore, embodiments of the present disclosure further
disclose a storage medium which may store a data processing
application. The data processing application may be used to execute
any of the foregoing embodiments of the methods of the present
disclosure.
[0172] Further, the method operations in above embodiments of the
present disclosure not only may be implemented via the data
processing application, but also may be implemented via hardware,
such as a logic gate, a switch, an application-specific integrated
circuit (ASIC), a programmable logic controller (PLC) and an
embedded microcontroller. Therefore, hardware, which may implement
the methods of the present disclosure, may constitute the
embodiments of the present disclosure.
[0173] While the present disclosure has been shown and described
with reference to various embodiments thereof, it will be
understood by those skilled in the art that various changes in form
and details may be made therein without departing from the spirit
and scope of the present disclosure as defined by the appended
claims and their equivalents.
* * * * *